Magnum and Solum don't have a liberty release yet

Remove liberty file for Magnum and Solum: the 2015.1.0 version
listed there is their Kilo version, and they haven't tagged a
Liberty release yet.

Change-Id: Iacaef0c103c5e8a478cde264a9ed22594d7e1870

deliverables/liberty/magnum.yaml

@@ -1,7 +0,0 @@
----
-launchpad: magnum
-releases:
-  - version: 2015.1.0
-    projects:
-      - repo: openstack/magnum
-        hash: 1c3027fc526181f8eb3e3831d278c79b0cf194d3

deliverables/liberty/solum.yaml

@@ -1,7 +0,0 @@
----
-launchpad: solum
-releases:
-  - version: 2015.1.0
-    projects:
-      - repo: openstack/solum
-        hash: 999ce4b2b7f03a3960381474a92df2bdb89010c6