librados: mark category args and ops as unused

Signed-off-by: Sage Weil <sage@redhat.com>
librados: add new get_pool_stats() variant; deprecate others

A new call will return a simple map of pool -> stats.  Drop the old ones
that did pool -> category -> stats, and deprecate the category one
entirely.

Signed-off-by: Sage Weil <sage@redhat.com>
librados: drop create category args

Signed-off-by: Sage Weil <sage@redhat.com>
osd: stop doing per-category accounting

Signed-off-by: Sage Weil <sage@redhat.com>
mon/PGMonitor: do not report per-category stats

Signed-off-by: Sage Weil <sage@redhat.com>
osd/osd_types: remove cat_sum from object_stat_collection_t

This type is now just a useless wrapper around object_stat_sum_t, but that
is not easy to drop.

Note that now if we load and reencode a legacy object we'll drop those
fields.  We would mark the incompat flag in the object corpus accordingly,
but nothing in there populates the cat fields.

Signed-off-by: Sage Weil <sage@redhat.com>
osd/osd_types: drop useless conditionals on object_info_t decode

The incompat decode version is 8, so we will never see struct_v < 5.

Signed-off-by: Sage Weil <sage@redhat.com>
PendingReleaseNotes: not about dropping category

Signed-off-by: Sage Weil <sage@redhat.com>
rados: change 'df' output now that categories are gone

Signed-off-by: Sage Weil <sage@redhat.com>
rados: drop optional 'create [category]' arg

Signed-off-by: Sage Weil <sage@redhat.com>
osd/ReplicatedPG: drop cateogry support from CREATE

Signed-off-by: Sage Weil <sage@redhat.com>
osdc/Objecter: drop category from copy-get

Signed-off-by: Sage Weil <sage@redhat.com>
osd/osd_types: drop category from object_info_t

Signed-off-by: Sage Weil <sage@redhat.com>
Merge pull request #2979 from ceph/wip-kill-category

osd: kill 'category' from pg_stats_t

Reviewed-by: Samuel Just <sjust@redhat.com>