librados: fix race on osdmap initialization

librados: fix race on osdmap initialization

This would cause occasional failures where calls
to lookup_pool immediately after connect() would
fail to find any pool because the OSD map had not
yet been loaded.  The wait for the map was lost when
the pool name cache was lost in ce176b827.

To avoid similar issues, the pool_requires_alignment
and pool_required_alignment helpers need the same
wait_for_osdmap before proceeding.  Usually callers
would call lookup_pool before these guys but it's
not guaranteed.

Signed-off-by: John Spray <john.spray@redhat.com>