Consolidate python memcache bindings install

Consolidate all the installs of python memcache
bindings to use ensure_package. Right now we are
mixing the usage of ensure_resources on some places
which causes redecalaration issues.

Since the resources need to be identical in order
to not raise redeclaration issues we cannot have
the horizon-package tag on the package.

Change-Id: I0a76cbe45774bbf6871c1803c056bc2f6b3b6c0d
(cherry picked from commit 3ec253827c)

manifests/init.pp

@@ -621,9 +621,10 @@ class horizon(
   validate_legacy(Stdlib::Absolutepath, 'validate_absolute_path', $root_path)
 
   if $manage_memcache_package and $cache_backend =~ /MemcachedCache/ {
-    ensure_resources('package', { 'python-memcache' =>
-      { name   => $::horizon::params::memcache_package,
-        tag    => ['openstack', 'horizon-package']}})
+    ensure_packages('python-memcache', {
+      name => $::horizon::params::memcache_package,
+      tag  => ['openstack'],
+    })
   }
 
   package { 'horizon':

spec/classes/horizon_init_spec.rb

@@ -295,7 +295,7 @@ describe 'horizon' do
 
       it {
         is_expected.to contain_package('python-memcache').with(
-          :tag    => ['openstack', 'horizon-package'],
+          :tag    => ['openstack'],
           :name   => platforms_params[:memcache_package],
          )
       }