Debian/Ubuntu: Fix priority setting to pin ceph packages

Since 13044d9f9e was merged, we use
the upstream ceph repo to pull packages for Ubuntu, and this broke
the priority setting to avoid installing ceph packages from UCA repo.

This change fixes that and ensure the priority is configured with
the ceph repo.

Backport note:
This change includes 972a226ab7 which
fixed the circular dependencies caused by the original change.

Change-Id: I7b187d59f169689a7acd5cab013bb74d5cdfbf52
(cherry picked from commit cfdf592942)
(cherry picked from commit 7d9fd6332b)

manifests/repos.pp

@@ -28,9 +28,11 @@ class openstack_integration::repos {
           fail("Unsupported package type (${::os_package_type})")
         }
       }
+
+      $ceph_mirror_fallback = pick($::ceph_mirror_host, "http://download.ceph.com/debian-${ceph_version_real}/")
       # Ceph is both packaged on UCA and official download.ceph.com packages
       # which we mirror. We want to use the official packages or our mirror.
-      if defined('$::nodepool_mirror_host') and $::nodepool_mirror_host != '' {
+      if $ceph_mirror_fallback !~ '^http://download.ceph.com/.*' {
         $ceph_version_cap = capitalize($ceph_version_real)
         apt::pin { 'ceph':
           priority   => 1001,
@@ -42,9 +44,10 @@ class openstack_integration::repos {
           origin   => 'download.ceph.com',
         }
       }
+
       $enable_sig  = false
       $enable_epel = false
-      $ceph_mirror = pick($::ceph_mirror_host, "http://download.ceph.com/debian-${ceph_version_real}/")
+      $ceph_mirror = $ceph_mirror_fallback
     }
     'RedHat': {
       if defined('$::centos_mirror_host') and $::centos_mirror_host != '' {