Handle out of transaction buffer in TC for INDX lookups

If ::exteral_lock hadn't been called, we'd have no NDB object,
so need to check/get one here.

It looks like sql_show.cc is the only place that does this....
or at least the other places will be well hidden.

Index: ndb-work/sql/ha_ndbcluster.cc
===================================================================

Reduce case and formalise into something we should be
able to use in mysql-test-run.

Index: ndb-work/mysql-test/t/ndb_bug26793.test
===================================================================

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb

into  perch.ndb.mysql.com:/home/jonas/src/mysql-5.0-ndb

  dont assert if 2 LCP's are being run during a node recovery

into  dev3-63.(none):/home/zhl/mysql/mysql-5.0/bug25941

into  perch.ndb.mysql.com:/home/jonas/src/mysql-5.0-ndb

  Not very clever fix for DIH incorrect REDO handling
  - Dont report GCP_SAVE_CONF until first LCP has been complete during NR

into  perch.ndb.mysql.com:/home/jonas/src/mysql-5.0-ndb

  In TC init node status for already started nodes during node restart
  (not present in 5.1)

  Fix 3 problems in REDO validation that could(will) lead to "Error while reading REDO log"

into  dev3-240.dev.cn.tlan:/home/justin.he/mysql/mysql-5.0/mysql-5.0-ndb-bj.merge

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb

- correct test and result file

into  dev3-240.dev.cn.tlan:/home/justin.he/mysql/mysql-5.0/mysql-5.0-ndb-bj.merge

into  mysql.com:/windows/Linux_space/MySQL/mysql-5.0-ndb

- correction, missing node id

into  mysql.com:/windows/Linux_space/MySQL/mysql-5.0-ndb

Bug#26342 auto_increment_increment AND auto_increment_offset REALLY REALLY anger NDB cluster, implemented support for auto_increment_offset and auto_increment_increment for Ndb, post review fix

into  dev3-240.dev.cn.tlan:/home/justin.he/mysql/mysql-5.0/bug27640-5.0-ndb

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb

- correction of merge error

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb

- make sure we close the first file, before opening the next

into  perch.ndb.mysql.com:/home/jonas/src/50-work

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb

  so that othernodes dont get confused after having recevied status from master
  and then tries to update it self