Cleanup after commit ac8e3c8

srv_conc_t::n_active: Correct the comment, and remove an
assertion that trivially holds now that the type is unsigned.

storage/innobase/srv/srv0conc.cc

@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2011, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2016, MariaDB Corporation.
+Copyright (c) 2015, 2018, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -73,11 +73,7 @@ ulong	srv_thread_concurrency	= 0;
 struct srv_conc_t {
 	char		pad[CACHE_LINE_SIZE  - (sizeof(ulint) + sizeof(lint))];
 
-	/** Number of transactions that have declared_to_be_inside_innodb set.
-	It used to be a non-error for this value to drop below zero temporarily.
-	This is no longer true. We'll, however, keep the lint datatype to add
-	assertions to catch any corner cases that we may have missed. */
-
+	/** Number of transactions that have declared_to_be_inside_innodb */
 	ulint	n_active;
 
 	/** Number of OS threads waiting in the FIFO for permission to
@@ -273,8 +269,6 @@ srv_conc_force_enter_innodb(
 		return;
 	}
 
-	ut_ad(srv_conc.n_active >= 0);
-
 	(void) my_atomic_addlint(&srv_conc.n_active, 1);
 
 	trx->n_tickets_to_enter_innodb = 1;