Remove lib/ceph

All jobs using ceph as a storage backend have been moved over
to using the devstack-plugin-ceph repo in project-config so we
should be safe to remove the now unused lib/ceph file.

The files are left in place because the devstack plugin does not
install xfsprogs but it's used by the create_disk function.

And the ceph cinder backend file is left in place since the
devstack-plugin-ceph repo uses that by setting
CINDER_ENABLED_BACKENDS=${CINDER_ENABLED_BACKENDS:-ceph}.

Change-Id: I3fb09fc92bc6ab614e86d701ea46d5741a76b7a8
diff --git a/functions-common b/functions-common
index 3fdd71b..6312188 100644
--- a/functions-common
+++ b/functions-common
@@ -1880,7 +1880,7 @@
             # white listed elements in tree. We want these to move out
             # over time as well, but they are in tree, so we need to
             # manage that.
-            local exceptions="60-ceph.sh 80-tempest.sh"
+            local exceptions="80-tempest.sh"
             local extra
             extra=$(basename $extra_plugin_file_name)
             if [[ ! ( $exceptions =~ "$extra" ) ]]; then