"Disabled plugin is provoking Valgrind error"
  If there are any auto-alloced string plug-in options, memory is
  allocated during the call for handle_options(). We must free this
  memory if we are not installing the plug-in.


include/my_getopt.h:
  bug31382
    new function: my_cleanup_options()
mysys/my_getopt.c:
  bug31382
    new function: my_cleanup_options(), fini_one_value()
    alter init_variables() to take an extra option.
    forward declare init_one_value() and fini_one_value()
sql/sql_plugin.cc:
  bug31382
    after calling handle_options(), make sure to call my_cleanup_options()
    if we are not installing the plug-in.