"Plugin Server Variables"
  Post review cleanups.


include/mysql/plugin.h:
  WL2936
    post review clean up
    fix macros to ensure correct type declarations
sql/ha_partition.cc:
  WL2936
    post review clean up
    add in missing my_afree()
sql/handler.cc:
  WL2936
    post review clean up
    remove stray semicolon
sql/sql_plugin.cc:
  WL2936
    post review clean up
    fixup comments and debug code
storage/innobase/handler/ha_innodb.cc:
  WL2936
    Include some of Marko Mäkelä's patches
storage/innobase/handler/ha_innodb.h:
  WL2936
    Include some of Marko Mäkelä's patches