Protect CEL from an invalid config on reload

This patch fixes CEL to properly handle an invalid config on reload.

(closes issue ASTERISK-22259)
Reported by: Corey Farrell
Tested by: Corey Farrell
Patches:
    cel-config.patch uploaded by Corey Farrell


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@397033 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/cel.c

@@ -310,7 +310,7 @@ static int do_reload(void)
 
 	config = ast_config_load2("cel.conf", "cel", config_flags);
 
-	if (config == CONFIG_STATUS_FILEMISSING) {
+	if (config == CONFIG_STATUS_FILEMISSING || config == CONFIG_STATUS_FILEUNCHANGED || config == CONFIG_STATUS_FILEINVALID) {
 		config = NULL;
 		goto return_cleanup;
 	}