Manually merged query cache fixes from
97c02faf0a39dd189eeda4f75fb35bc5db69d541.

- Eliminates code duplication in query cache patch
- Reduces the number of iterations in mysql-wsrep#201.test
  to shorten the execution time
- Adds a new test case that exercises more scenarios

- Fixes query cache so that it is aware of wsrep_sync_wait.
  Query cache would return (possibly stale) results to the
  client, regardless of the value of wsrep_sync_wait.
- Includes the test case that reproduced the issue.

Addendum: Save thd's server_status & option_bits before
setting the thread specific pointer.

As a fix for MDEV-8208, for initial wsrep threads, the
invocation of init_for_queries() was moved after plugins
were initialized. Due to which, OPTION_BEGIN bit of wsrep
applier THD (originally set in wsrep_replication_process)
got reset due to implicit commit within init_for_queries().
As a result, events from a multi-statement transaction from
another node were committed separately by the applier thread,
which leads to an assertion as they all carry same seqno.

Fixed by making sure that variable.option_bits are restored
post init_for_queries(). Also restored server_status.
Added a test case.

The License field in the MariaDB RPM packages is GPL. This does not tell
the version of GPL and might confuse tools and users that rely on this
field.

Best practice in the RPM world is to use "GPLv2" for the GPL 2.0
license.

The commit switches the license field of the RPM packages to GPLv2.

5.5.46-37.6

Removed unused variable.

MDEV-8825 mysql_upgrade leaks the admin password when it spawns a shell process to execute mysqlcheck

don't put common arguments on the command-line,
use a config file instead

Reimplement ssl_verify_server_cert() using the logic
from https://wiki.openssl.org/index.php/Hostname_validation

The bug was discovered by Alex Gaynor.

first close all tables, then unload UDFs

thd->cleanup_after_query() is needed to destroy all Items
created for this query (and Item destructors free allocated
Strings).

set keep_row_order=true for temporary tables that
hold results of the SHOW command

5.5 patch only

use --mysqld instead of naming all groups explicitly

https://github.com/MariaDB/server/pull/92

Don't let network errors from mysql_close() leak into THD.

* remove incorrect upstream fix
** table->in_use can be NULL, must use ha_thd()
** clear_error() may remove earlier errors, don't use it
* fix the bug properly in federated and federatedx

* reduce code duplication
* change int->void for the function that doesn't return an error
* use ha_thd()

fix innodb auto-increment handling
three bugs:
1. innobase_next_autoinc treated the case of current<offset incorrectly
2. ha_innobase::get_auto_increment didn't recalculate current when increment changed
3. ha_innobase::get_auto_increment didn't pass offset down to innobase_next_autoinc

debian/additions/my.cnf sets slow_query_log_file to
/var/log/mysql/mariadb-slow.log.

Update the filename to rotate the slow log file.

Incorrect array lenght for comma buffer.

Analysis: There were two problems. (1) if partition table was
created using lower_case_tables = 1 on windows we did find the
correct table but we did not set share->ib_table correctly.
(2) we did open table on dictionary but did not increase
mysql_open_tables.

Fix: In xtradb allow access to tables with incorrect
lower case names (warning is printed to error log). If
table is opened increase mysql_open_tables count to avoid
crash on flush tables.

Item_func_coalesce::fix_length_and_dec() calls
Item_func::count_string_result_length()) which called agg_arg_charsets()
with wrong flags, so the collation derivation of the COALESCE result was
not properly set to DERIVATION_COERCIBLE. It erroneously stayed
DERIVATION_NUMERIC. So GREATEST() misinterpreted the argument as
a number rather that a string and did not calculate its own length properly.

mysqldump --routine fails to dump databases containing backslash ("\")
character. This happened because escaped database name was being used as an
identifier while changing current database. Such identifers are not supposed
to be escaped, they must be properly quoted instead.

Analysis: debug only assertion I_S function (IS is XtraDB feature) is calling
buf_block_get_frame on any page it reads, which debug-asserts that the page is
buffer-fixed, which is not the case in I_S query.

Fixed by holding the buffer page mutex while the fields are read directly.

Non-select-like queries has no correct JOIN structure connected to top-most SELECT_LEX (and should not).

feedback plugin needs to set tables->select_lex properly

make it possible to change feedback plugin wait intervals
* only in debug builds
* and force the feedback report to be ignored

update the test to use this feature