Remove duplicate stdlib.h include.

(closes issue #11105)
Reported by: eliel
Patches:
      app_voicemail.c.patch uploaded by eliel (license 64)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@87327 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_voicemail.c

@@ -69,7 +69,6 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include <errno.h>
 #include <unistd.h>
 #include <string.h>
-#include <stdlib.h>
 #include <stdio.h>
 #include <sys/time.h>
 #include <sys/stat.h>