Added 'have_innodb_disallow_writes.inc'.

mysql-test/include/have_innodb_disallow_writes.inc

+--source include/have_innodb.inc
+
+if (`SELECT COUNT(*) = 0 from INFORMATION_SCHEMA.GLOBAL_VARIABLES
+    WHERE VARIABLE_NAME = 'INNODB_DISALLOW_WRITES'`) {
+  --skip Test requires 'innodb_disallow_writes'
+}

mysql-test/include/have_wsrep.inc

@@ -3,6 +3,6 @@
 
 if (`SELECT COUNT(*)=0 FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME = 'wsrep' AND PLUGIN_STATUS='ACTIVE'`)
 {
-  --skip Test required wsrep plugin.
+  --skip Test requires wsrep plugin.
 }