Make mongo install for ceilometer NOPRIME

mongodb packages are missing on some platforms, so we switch to a
manual install.  Also gate the mongo call in cleanup

Change-Id: I1755e461c66be30da3db2a0994f908503c4c38ea
diff --git a/files/apts/ceilometer-collector b/files/apts/ceilometer-collector
index 71007ba..f1b692a 100644
--- a/files/apts/ceilometer-collector
+++ b/files/apts/ceilometer-collector
@@ -1,5 +1,5 @@
-python-pymongo
-mongodb-server
+python-pymongo #NOPRIME
+mongodb-server #NOPRIME
 libnspr4-dev
 pkg-config
 libxml2-dev