Import of code from heimdal

This commit updates the code imported from heimdal to
66f4c441e9e0de68fbcf81763642779ac5c33631 (git2svn-syncpoint-master-199-g66f4c44)

Upstream changes are:

Kumar Thangavelu (1):
      unning "kinit --fast-armor-cache=xxx" against a Win2K3 domain resulted in a crash with the attached backtrace. FAST is not supported with RC4 keys which are used in Win2K3. The code already handles this but the error code is not propagated up the stack.

Love Hornquist Astrand (1):
      add socket_set_nonblocking

Roland C. Dowdeswell (3):
      Optimise _krb5_n_fold() a bit.
      Use krb5_enomem() more consistently in lib/krb5.
      Further improvements to lib/krb5/n-fold.c:

Change-Id: I3b652e3ea3c84a939c4988bc8c24b3edee06446f
Reviewed-on: http://gerrit.openafs.org/9264
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: Derrick Brashear <shadow@your-file-system.com>