Don't uninstall ceph packages at cleanup

We stop the services, which should be sufficient.
Uninstalling the packages means that doing repeated
runs with devstack takes longer than necessary.

Change-Id: I5626e42ce83710690a3523439bb2c9c9af560cd9
diff --git a/lib/ceph b/lib/ceph
index 16dcda2..04e05e7 100644
--- a/lib/ceph
+++ b/lib/ceph
@@ -158,7 +158,6 @@
 
 function cleanup_ceph_general {
     undefine_virsh_secret
-    uninstall_package ceph ceph-common python-ceph libcephfs1 > /dev/null 2>&1
 }