After-merge fix: clang -Winconsistent-missing-override

The virtual member function that was added in
commit 1766a18e
needs to be declared "override".

storage/innobase/handler/ha_innodb.h

@@ -459,7 +459,7 @@ class ha_innobase final: public handler
 	/* @return true if it's necessary to switch current statement log
 	format from STATEMENT to ROW if binary log format is MIXED and
 	autoincrement values are changed in the statement */
-	bool autoinc_lock_mode_stmt_unsafe() const;
+	bool autoinc_lock_mode_stmt_unsafe() const override;
 	dict_index_t* innobase_get_index(uint keynr);
 
 #ifdef WITH_WSREP