Ticket History #8792: Implement krb5_cc_remove_cred for remaining types

Implement krb5_cc_remove_cred for remaining types

Previously, only KCM and MSLA implemented credential removal. Add
support for FILE (and therefore DIR), MEMORY, and KEYRING.

The FILE logic is similar Heimdal's implementation, with additional
logic for skipping removed creds during iteration. In addition to
setting endtime to 0 and changing the realm for config entries as
Heimdal does, we set authtime to -1 to make deleted entries
distinguishable from gssproxy encrypted creds and config entries.

For MEMORY, leave behind empty list elements when removing a cred will
leave behind an empty list element, in case an iterator holds a
pointer to that element.

[ghudson@mit.edu: edited commit message; made minor style and comment
changes; fixed memory leaks detected by asan]

https://github.com/krb5/krb5/commit/d3b39a8bac6206b5ea78b0bf6a2958c1df0b0dd5
Author: Robbie Harwood <rharwood@redhat.com>
Committer: Greg Hudson <ghudson@mit.edu>
Commit: d3b39a8bac6206b5ea78b0bf6a2958c1df0b0dd5
Branch: master
src/lib/krb5/ccache/cc_file.c | 177 +++++++++++++++++++++++++++++++++++---
src/lib/krb5/ccache/cc_keyring.c | 89 +++++++++++++------
src/lib/krb5/ccache/cc_memory.c | 36 +++++++--
src/lib/krb5/ccache/t_cc.c | 129 +++++++++++++++++++++++++++-
4 files changed, 381 insertions(+), 50 deletions(-)

Fix potential close(-1) in cc_file.c

As part of error handling in d3b39a8bac6206b5ea78b0bf6a2958c1df0b0dd5,
an error path in delete_cred() may result in close(-1). While this
shouldn't be a prolblem in practice (just returning EBADF), it does
upset Coverity.

https://github.com/krb5/krb5/commit/5ccfbaf2f0c8871d2f0ea87ad4b21cc33392ca2c
Author: Robbie Harwood <rharwood@redhat.com>
Committer: Greg Hudson <ghudson@mit.edu>
Commit: 5ccfbaf2f0c8871d2f0ea87ad4b21cc33392ca2c
Branch: master
src/lib/krb5/ccache/cc_file.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)