Bug #24488141 ACTIVE UNDO TABLESPACE NOT UPDATED WHEN INNODB_UNDO_LOGS IS INCREASED

Problem:
========
 If we increase innodb_undo_logs value during startup. New rollback
segment might get allocated during trx_sys_create_rseg(). Essentially, it
would make these tablesapces active with transaction undo data and purge.
But it doesn't come in active undo tablespaces. so these tablespace would
never get truncated.

Fix:
===
 Increase the number of active undo tablespace when we are assigning the
undo tablespace to the newly assigned rollback segment.
Reviewed-by: Kevin Lewis <kevin.lewis@oracle.com>
Reviewed-by: Debarun Banerjee <debarun.banerjee@oracle.com>
RB: 13746

storage/innobase/trx/trx0sys.cc

@@ -921,6 +921,15 @@ trx_sys_create_rsegs()
 					" requested innodb_undo_logs";
 				return(false);
 			}
+
+			/* Increase the number of active undo
+			tablespace in case new rollback segment
+			assigned to new undo tablespace. */
+			if (space > srv_undo_tablespaces_active) {
+				srv_undo_tablespaces_active++;
+
+				ut_ad(srv_undo_tablespaces_active == space);
+			}
 		}
 	}