debian: ceph-dbg steals ceph-objectstore-tool from ceph-test-dbg

debian: ceph-dbg steals ceph-objectstore-tool from ceph-test-dbg

When ceph-objectstore-tool was moved from ceph-test to
ceph by 61cf5da0b51e2d9578c7b4bca85184317e30f4ca, the ceph package in
debian/control was updated accordingly, as recommended by
https://www.debian.org/doc/debian-policy/ch-relationships.html#s-replaces

The same must be done for the ceph-dbg package because
/usr/lib/debug/usr/bin/ceph-objectstore-too is no longer in
ceph-test-dbg.

Although the change was merged may 6th, 2015
8f23382064c189b657564d58c3f9d17720e891ed, teuthology jobs were not
always failing because packages were not systematically upgraded during
the installation. The missing dependencies that were responsible for
this upgrade problem were fixed by
f898ec1e4e3472b0202280f09653a769fc62c8d3 on may 18th, 2015 and all
upgrade tests relying on ceph-*-dbg packages started to fail
systematically after this date.

http://tracker.ceph.com/issues/11546 Fixes: #11546

Signed-off-by: Loic Dachary <ldachary@redhat.com>