w/o definer if --skip-grant-tables specified.
  
The previous patch does not allow to specify empty host name in
DEFINER-clause explicitly.


mysql-test/r/skip_grants.result:
  Updated the result file.
mysql-test/r/view_grant.result:
  Updated the result file.
mysql-test/t/skip_grants.test:
  Added test cases for BUG#16777; re-organized tests.
mysql-test/t/view_grant.test:
  Updated after final fix of BUG#16777.
sql/sql_parse.cc:
  The final part of fixing BUG#16777: allow empty host name in explicitly
  specified DEFINER-clause.
sql/sql_show.cc:
  Quote an identifier if it is empty.