The KCM server returns KRB5_CC_END in response to a GET_CACHE_BY_UUID
request to indicate that the specified ccache uuid no longer exists.
In krb5_ptcursor_next(), ignore this error and continue the iteration,
as the Heimdal KCM client code does.
In addition to addressing the case where a third party deletes a cache
between the GET_CACHE_UUID_LIST request and when we reach that uuid in
the iteration, this change also fixes a bug in kdestroy -A where the
caller deletes the primary cache and we later request it by uuid when
iterating over the list.