gfs2: Initialize atime of I_NEW inodes

Fix for commit 719ee344

: initialize atime of I_NEW inodes to 0 so that
the timestamps read from disk will always be more recent than the
initial timestamp, and the atime in the I_NEW inode will be set correctly.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>