selinux: remove redundant assignment to len

The variable len is being set to zero and this value is never
being read since len is being set to a different value just
a few lines later.  Remove this redundant assignment. Cleans
up clang warning: Value stored to 'len' is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

security/selinux/ss/conditional.c

@@ -361,7 +361,6 @@ static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list *
 
 	*ret_list = NULL;
 
-	len = 0;
 	rc = next_entry(buf, fp, sizeof(u32));
 	if (rc)
 		return rc;