config: Fix inverted test

The test of the result of the stat() call was inverted such that its
output was only used if the call failed. This inverts the test so that
the output of stat() is used correctly. This was causing full reloads
on unchanged files.

(closes issue ASTERISK-23383)
Reported by: David Woolley
........

Merged revisions 409916 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@409917 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/config.c

@@ -1266,7 +1266,7 @@ static void config_cache_attribute(const char *configfile, enum config_cache_att
 		AST_LIST_INSERT_SORTALPHA(&cfmtime_head, cfmtime, list, filename);
 	}
 
-	if (!stat(configfile, &statbuf)) {
+	if (stat(configfile, &statbuf)) {
 		cfmstat_clear(cfmtime);
 	} else {
 		cfmstat_save(cfmtime, &statbuf);