eCryptfs: Copy lower directory inode times and size on link

The timestamps and size of a lower inode involved in a link() call was
being copied to the upper parent inode.  Instead, we should be
copying lower parent inode's timestamps and size to the upper parent
inode.  I discovered this bug using the POSIX test suite at Tuxera.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>