SQUASH: OSD: do not share OSD maps with peers that already have them

We were looking at the recorded peer epoch, but if that was older than
the epoch the current message was sent in, we still send the map. Don't.

Signed-off-by: Greg Farnum <greg@inktank.com>
FIXUP "SQUASH 'msgr: enable fast_dispatch on local connections'"

Signed-off-by: Greg Farnum <greg@inktank.com>