res_agi.c:handle_getvariablefull() could recursively lock a channel and not

release it if an argument is the current channel's name.

(closes issue #17970)
Reported by: mdu113
Patches: 
      res_agi.c.diff3 uploaded by mdu113 (license 582)
      Tested by: mdu113

      Review: https://reviewboard.asterisk.org/r/947/


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@289500 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_agi.c

@@ -1240,7 +1240,7 @@ static int handle_getvariablefull(struct ast_channel *chan, AGI *agi, int argc,
 
 	if ((argc != 4) && (argc != 5))
 		return RESULT_SHOWUSAGE;
-	if (argc == 5) {
+	if (argc == 5 && strcasecmp(chan->name, argv[4])) {
 		chan2 = ast_get_channel_by_name_locked(argv[4]);
 	} else {
 		chan2 = chan;