confbridge: Add Duration to ConfbridgeList event

The ConfbridgeList event doesn't include how long the user has been a
member of the conference.  This patch adds Duration (seconds) which
is based on user->chan->answertime.

Tested by: George Joseph
Review: https://reviewboard.asterisk.org/r/3955/
........

Merged revisions 422444 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@422445 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_confbridge.c

@@ -2837,6 +2837,7 @@ static void action_confbridgelist_item(struct mansession *s, const char *id_text
 		"EndMarked: %s\r\n"
 		"Waiting: %s\r\n"
 		"Muted: %s\r\n"
+		"AnsweredTime: %d\r\n"
 		"\r\n",
 		id_text,
 		conference->name,
@@ -2848,7 +2849,8 @@ static void action_confbridgelist_item(struct mansession *s, const char *id_text
 		ast_test_flag(&user->u_profile, USER_OPT_WAITMARKED) ? "Yes" : "No",
 		ast_test_flag(&user->u_profile, USER_OPT_ENDMARKED) ? "Yes" : "No",
 		waiting ? "Yes" : "No",
-		user->muted ? "Yes" : "No");
+		user->muted ? "Yes" : "No",
+		ast_channel_get_up_time(user->chan));
 }
 
 static int action_confbridgelist(struct mansession *s, const struct message *m)