Fix a bug, whereby nfs_update_inode() was declaring the inode to be
up to date despite not having checked all the attributes.
The bug occurs because the temporary variable in which we cache
the validity information is 'sanitised' before reapplying to
nfsi->cache_validity.
Reported-by: NKinglong Mee <kinglongmee@gmail.com>
Cc: stable@vger.kernel.org # 3.5+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>