handle edgecase leak on platforms without vasprintf. Found by Klockwork (www.klocwork.com)

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@8445 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/switch_event.c

@@ -863,11 +863,14 @@ SWITCH_DECLARE(switch_xml_t) switch_event_xmlize(switch_event_t *event, const ch
 		ret = vasprintf(&data, fmt, ap);
 #else
 		data = (char *) malloc(2048);
-		switch_assert(data);
+		if (!data) return NULL;
 		ret = vsnprintf(data, 2048, fmt, ap);
 #endif
 		va_end(ap);
 		if (ret == -1) {
+#ifndef HAVE_VASPRINTF
+			free(data);
+#endif
 			return NULL;
 		}
 	}