Title: #722: KCM: Deleting a non-existent ccache should not yield an error
When the KCM destroy operation is called, it receives a name as an input.
If the name cannot be found, we would currently return KRB5_CC_NOTFOUND.
But other ccache types return KRB5_FCC_NOFILE in that case and e.g.
utilities like kdestroy special case KRB5_FCC_NOFILE to be non-fatal.
To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/722/head:pr722
git checkout pr722