Don't try to change working directory if a directory was not configured.

(closes issue #14089)
Reported by: caspy


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@164605 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_musiconhold.c

@@ -481,7 +481,7 @@ static int spawn_mp3(struct mohclass *class)
 			}
 		}
 		/* Child */
-		if (chdir(class->dir) < 0) {
+		if (strcasecmp(class->dir, "nodir") && chdir(class->dir) < 0) {
 			ast_log(LOG_WARNING, "chdir() failed: %s\n", strerror(errno));
 			_exit(1);
 		}