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

Commit a5bca4ef034f71175d46462963af2329d22068c2 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;
 	}