fix more sql_command_flags:

  SQLCOM_ASSIGN_TO_KEYCACHE should not be CF_AUTO_COMMIT_TRANS
  SQLCOM_PRELOAD_KEYS should not be CF_AUTO_COMMIT_TRANS
  SQLCOM_INSTALL_PLUGIN should need CF_AUTO_COMMIT_TRANS
  SQLCOM_UNINSTALL_PLUGIN should need CF_AUTO_COMMIT_TRANS

sql/sql_parse.cc

@@ -428,8 +428,8 @@ void init_update_queries(void)
   sql_command_flags[SQLCOM_DROP_FUNCTION]=     CF_CHANGES_DATA | CF_AUTO_COMMIT_TRANS;
   sql_command_flags[SQLCOM_ALTER_PROCEDURE]=   CF_CHANGES_DATA | CF_AUTO_COMMIT_TRANS;
   sql_command_flags[SQLCOM_ALTER_FUNCTION]=    CF_CHANGES_DATA | CF_AUTO_COMMIT_TRANS;
-  sql_command_flags[SQLCOM_INSTALL_PLUGIN]=    CF_CHANGES_DATA;
-  sql_command_flags[SQLCOM_UNINSTALL_PLUGIN]=  CF_CHANGES_DATA;
+  sql_command_flags[SQLCOM_INSTALL_PLUGIN]=    CF_CHANGES_DATA | CF_AUTO_COMMIT_TRANS;
+  sql_command_flags[SQLCOM_UNINSTALL_PLUGIN]=  CF_CHANGES_DATA | CF_AUTO_COMMIT_TRANS;
 
   /*
     The following is used to preserver CF_ROW_COUNT during the
@@ -480,9 +480,6 @@ void init_update_queries(void)
   sql_command_flags[SQLCOM_GRANT]|=             CF_AUTO_COMMIT_TRANS;
   sql_command_flags[SQLCOM_GRANT_ROLE]|=        CF_AUTO_COMMIT_TRANS;
 
-  sql_command_flags[SQLCOM_ASSIGN_TO_KEYCACHE]= CF_AUTO_COMMIT_TRANS;
-  sql_command_flags[SQLCOM_PRELOAD_KEYS]=       CF_AUTO_COMMIT_TRANS;
-
   sql_command_flags[SQLCOM_FLUSH]=              CF_AUTO_COMMIT_TRANS;
   sql_command_flags[SQLCOM_RESET]=              CF_AUTO_COMMIT_TRANS;
   sql_command_flags[SQLCOM_CREATE_SERVER]=      CF_AUTO_COMMIT_TRANS;
@@ -3034,7 +3031,6 @@ case SQLCOM_PREPARE:
     break;
   }
   case SQLCOM_CREATE_INDEX:
-    /* Fall through */
   case SQLCOM_DROP_INDEX:
   /*
     CREATE INDEX and DROP INDEX are implemented by calling ALTER