Fix a memory leak on aborted InnoDB startup.

innodb_shutdown(), trx_sys_close(): Startup may be aborted between
purge_sys and trx_sys creation. Therefore, purge_sys must be freed
independently of trx_sys.

innobase_start_or_create_for_mysql(): Remember to free purge_queue if
it was not yet attached to purge_sys.

storage/innobase/srv/srv0start.cc

@@ -2206,6 +2206,7 @@ innobase_start_or_create_for_mysql(void)
 			DBUG_PRINT("ib_log", ("apply completed"));
 
 			if (err != DB_SUCCESS) {
+				UT_DELETE(purge_queue);
 				return(srv_init_abort(err));
 			}
 
@@ -2280,6 +2281,7 @@ innobase_start_or_create_for_mysql(void)
 					" a startup if you are trying to"
 					" recover a badly corrupt database.";
 
+				UT_DELETE(purge_queue);
 				return(srv_init_abort(DB_ERROR));
 			}
 		}
@@ -2796,6 +2798,9 @@ innodb_shutdown()
 		trx_sys_file_format_close();
 		trx_sys_close();
 	}
+	if (purge_sys) {
+		trx_purge_sys_close();
+	}
 	if (buf_dblwr) {
 		buf_dblwr_free();
 	}

storage/innobase/trx/trx0sys.cc

@@ -1092,10 +1092,6 @@ trx_sys_close(void)
 		trx_dummy_sess = NULL;
 	}
 
-	if (purge_sys) {
-		trx_purge_sys_close();
-	}
-
 	/* Only prepared transactions may be left in the system. Free them. */
 	ut_a(UT_LIST_GET_LEN(trx_sys->rw_trx_list) == trx_sys->n_prepared_trx
 	     || !srv_was_started