There can be only one ... MD5

There can be only one ... MD5

The cache manager has two implementations of md5 - one in afs_md5.c
(used by afs_NewCell) and one in afs_util.c - used by Linux's MD5-inode
code.

Remove the one in afs_util.c in favour of using the common
implementation in afs_md5.c

Reviewed-on: http://gerrit.openafs.org/572
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>