OSD: ping tphandle during pg removal

Fixes: #6528
Signed-off-by: Samuel Just <sam.just@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

(cherry picked from commit c658258d9e2f590054a30c0dee14a579a51bda8c)

Conflicts:
	src/osd/OSD.cc