Fixes to get securID preauth plugin working. A separate patch will
address error handling and build issues.

* Permit a preauth plugin to return KRB5KDC_ERR_PREAUTH_REQUIRED from
  the verify entry point.

* If verify_securid2 fails, save the return value and return that
  rather than success after dealing with encoding the out_edata

* Use the client key not the securid principal key for the sam
  checksum

* indicate that securID is hardware authentication

https://github.com/krb5/krb5/commit/b066ddfa869b362f7055b2532977a0f2d3860b35
Commit By: hartmans
Revision: 24465
Changed Files:
U   trunk/src/kdc/kdc_preauth.c
U   trunk/src/plugins/preauth/securid_sam2/extern.h
U   trunk/src/plugins/preauth/securid_sam2/securid2.c
U   trunk/src/plugins/preauth/securid_sam2/securid_sam2_main.c