launch_netscript sometimes returns -1, which fails to set AGISTATUS. Map

failure to -1, so that AGISTATUS is always set.
(closes issue #13199)
 Reported by: smw1218


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@134480 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_agi.c

@@ -112,9 +112,9 @@ static int agidebug = 0;
 #define AGI_PORT 4573
 
 enum agi_result {
+	AGI_RESULT_FAILURE = -1,
 	AGI_RESULT_SUCCESS,
 	AGI_RESULT_SUCCESS_FAST,
-	AGI_RESULT_FAILURE,
 	AGI_RESULT_HANGUP
 };