HTools/Types.hs: minor adjustments to auto-repair types
HTools/Types.hs: minor adjustments to auto-repair types

In particular:

  - make ArHealthy take an optional AutoRepairData; this allows to
    represent the situation where a repair completed successfully, and
    hence there's an associated tag we might want to know about.

  - add an 'arTag' member to AutoRepairData to store the exact tag this
    data was derived from; this allows for easier removal of the tag when
    its associated state is superseded. It also stores the tag that will
    be written to the cluster when a new AutoRepairData record is created.

  - change the default sort order of AutoRepairResult to reflect the
    precedence used when reading tags from an object (a failure, if
    present, is always the resulting state; a success overrides an
    ENOPERM).

  - (trivial) make AutoRepairStatus and AutoRepairData derive Eq and Show.

Signed-off-by: Dato Simó <16293852a0900193fe70fa7d24f714f37ba99a56@google.com>
Reviewed-by: Iustin Pop <acf83a5274f31a43af6b914614365999469c1a31@google.com>

leshchevds/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,mbakke/ganeti,onponomarev/ganeti,leshchevds/ganeti,grnet/snf-ganeti,apyrgio/ganeti,ganeti/ganeti,ganeti-github-testing/ganeti-test-1,ganeti/ganeti,andir/ganeti,andir/ganeti,apyrgio/ganeti,ganeti/ganeti,onponomarev/ganeti,dimara/ganeti,ganeti-github-testing/ganeti-test-1,andir/ganeti,yiannist/ganeti,mbakke/ganeti,leshchevds/ganeti,grnet/snf-ganeti,bitemyapp/ganeti,yiannist/ganeti,dimara/ganeti,bitemyapp/ganeti,apyrgio/snf-ganeti,yiannist/ganeti