debian: include rgw-gap-list manpage in ceph-common

The rgw-gap-list manpage was added to RPM packaging in commit 8d0ec76
but was omitted from the Debian package. Add it to ceph-common to align
with the RPM packaging, where both the executable and manpage are
included together.

Signed-off-by: Kefu Chai <[email protected]>

Author: tchaikov

debian/ceph-common.install

@@ -42,6 +42,7 @@ usr/share/man/man8/mount.ceph.8
 usr/share/man/man8/rados.8
 usr/share/man/man8/radosgw-admin.8
 usr/share/man/man8/rgw-policy-check.8
+usr/share/man/man8/rgw-gap-list.8
 usr/share/man/man8/rbd.8
 usr/share/man/man8/rbdmap.8
 usr/share/man/man8/rbd-replay*.8