channels/chan_mgcp: Fix regression which causes gateways to be skipped

In r227276, a while loop was turned into a for loop. Unfortunately, a portion
of the while loop was left in the code such that, when a static gateway is
encountered in the list of MGCP gateways, the next gateway would be skipped.
At best, we would simply flip past a gateway; at worst, this could lead to a
crash.

ASTERISK-24500 #close
Reported by: Xavier Hienne
patches:
  chan_mgcp.patch uploaded by Xavier Hienne (License 6657)
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Merged revisions 427613 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 427614 from http://svn.asterisk.org/svn/asterisk/branches/12
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Merged revisions 427615 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@427616 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_mgcp.c

@@ -1835,17 +1835,12 @@ static struct mgcp_subchannel *find_subchannel_and_lock(char *name, int msgid, s
 			/* not dynamic, check if the name matches */
 			} else if (name) {
 				if (strcasecmp(g->name, at)) {
-					g = g->next;
 					continue;
 				}
 			/* not dynamic, no name, check if the addr matches */
 			} else if (!name && sin) {
 				if ((g->addr.sin_addr.s_addr != sin->sin_addr.s_addr) ||
 				    (g->addr.sin_port != sin->sin_port)) {
-					if(!g->next)
-						g = find_realtime_gw(name, at, sin);
-					else
-						g = g->next;
 					continue;
 				}
 			} else {