ima: change the default hash algorithm to SHA1 in ima_eventdigest_ng_init()

ima: change the default hash algorithm to SHA1 in ima_eventdigest_ng_init()

commit c502c78ba7fb5b9cef71e2bd70f12c38ef26e5ab upstream.

Replace HASH_ALGO__LAST with HASH_ALGO_SHA1 as the initial value of
the hash algorithm so that the prefix 'sha1:' is added to violation
digests.

Fix commit:
  4d7aeee ima: define new template ima-ng and template fields d-ng and n-ng

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>