[PATCH] unshare: Error if passed unsupported flags

A bare bones trivial patch to ensure we always get -EINVAL on the
unsupported cases for sys_unshare.  If this goes in before 2.6.16 it allows
us to forward compatible with future applications using sys_unshare.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: JANAK DESAI <janak@us.ibm.com>
Cc: <stable@kerenl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>