Remove include userdefs.h where not needed

@@ -32,11 +32,10 @@
  */
 
 #include <errno.h>
 #include <sys/types.h>
 #include <stdio.h>
-#include <userdefs.h>
 #include <pwd.h>
 #include <libcmdutils.h>
 
 static int findunuseduid(uid_t start, uid_t stop, uid_t *ret);
 static boolean_t isreserveduid(uid_t uid);