[AUDIT] Fix signedness of 'serial' in various routines.

Attached is a patch that corrects a signed/unsigned warning. I also noticed
that we needlessly init serial to 0. That only needs to occur if the kernel
was compiled without the audit system.

-Steve Grubb

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/include/linux/audit.h b/include/linux/audit.h
index fad0c1d..0467f24 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -186,7 +186,7 @@
 extern int  audit_receive_filter(int type, int pid, int uid, int seq,
 				 void *data);
 extern void audit_get_stamp(struct audit_context *ctx,
-			    struct timespec *t, int *serial);
+			    struct timespec *t, unsigned int *serial);
 extern int  audit_set_loginuid(struct audit_context *ctx, uid_t loginuid);
 extern uid_t audit_get_loginuid(struct audit_context *ctx);
 extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode);