Remove setting wcc pre attrs.

Since we can't guarantee anything is atomic (unless a single Ganesha
instance is the ONLY interface to the filesystem in question), May be
we should not provide the pre-op attr. which will force the client to
look at the post-op attr to invalidate. The fact that the post op attr
is not atomic should not  be a problem, it is as fresh as can be when
Ganesha gets it, to whatever degree of atomicity it represents.

Signed-off-by: Venkateswararao Jujjuri "<jvrao@linux.vnet.ibm.com>