Fix inadvertent semantics change in last patch to plug memory leaks.

Commit a5bca4ef03 accidentally changed
the semantics when the "skipping missing configuration file" is
emitted, because it forced OK to true instead of leaving the value
untouched.

Spotted by Tom Lane.

src/backend/utils/misc/guc-file.l

@@ -476,7 +476,6 @@ ParseConfigFile(const char *config_file, const char *calling_file, bool strict,
 		ereport(LOG,
 				(errmsg("skipping missing configuration file \"%s\"",
 						abs_path)));
-		OK = true;
 		goto cleanup;
 	}