Fix unlikely null dereference in mk_cred()

Fix unlikely null dereference in mk_cred()

If krb5_encrypt_keyhelper() returns an error, the ciphertext structure
may contain a non-zero length, but it will already have freed the
pointer to its data, making encrypt_credencpart()'s subsequent attempt
to clear and free the memory fail.  Remove that logic.

Based on a patch from Jatin Nansi.

(cherry picked from commit 476284de8dc9a52b5544445cb1b316a417ae88f0)

ticket: 8107 (new)
version_fixed: 1.11.6
status: resolved