chan_iax2.c: Fix ref leak in iax2_request().

* Increased warning message format capability string buffer size in
iax2_request().

Review: https://reviewboard.asterisk.org/r/4601/
........

Merged revisions 434510 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@434511 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_iax2.c

@@ -12464,16 +12464,18 @@ static struct ast_channel *iax2_request(const char *type, struct ast_format_cap
 		if (!ast_format_cap_count(joint)) {
 			struct ast_format *best_fmt_cap = NULL;
 			struct ast_format *best_fmt_native = NULL;
+
 			res = ast_translator_best_choice(cap, ast_channel_nativeformats(c), &best_fmt_cap, &best_fmt_native);
 			if (res < 0) {
-				struct ast_str *native_cap_buf = ast_str_alloca(64);
+				struct ast_str *native_cap_buf = ast_str_alloca(256);
-				struct ast_str *cap_buf = ast_str_alloca(64);
+				struct ast_str *cap_buf = ast_str_alloca(256);
 
 				ast_log(LOG_WARNING, "Unable to create translator path for %s to %s on %s\n",
 					ast_format_cap_get_names(ast_channel_nativeformats(c), &native_cap_buf),
 					ast_format_cap_get_names(cap, &cap_buf),
 					ast_channel_name(c));
 				ast_hangup(c);
+				ao2_ref(joint, -1);
 				return NULL;
 			}
 			ast_format_cap_append(joint, best_fmt_native, 0);