If poll returns 0, force *ms to 0

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@5502 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channel.c

@@ -1126,6 +1126,12 @@ struct ast_channel *ast_waitfor_nandfds(struct ast_channel **c, int n, int *fds,
 #endif			
 		}
 		return NULL;
+        } else {
+        	/* If no fds signalled, then timeout. So set ms = 0
+		   since we may not have an exact timeout.
+		*/
+		if (res == 0)
+			*ms = 0;
 	}
 
 	if (havewhen)