[openstack|volume] Added missing service declaration

- Fixes regresion probably caused by eb0545b
- Added minimal test to catch the issue
- Fixes #1605

lib/fog/bin/openstack.rb

@@ -13,6 +13,8 @@ class OpenStack < Fog::Bin
         Fog::Network::OpenStack
       when :storage
         Fog::Storage::OpenStack
+      when :volume
+        Fog::Volume::OpenStack
       else
         raise ArgumentError, "Unrecognized service: #{key}"
       end
@@ -36,6 +38,9 @@ class OpenStack < Fog::Bin
         when :storage
           Fog::Logger.warning("OpenStack[:storage] is not recommended, use Storage[:openstack] for portability")
           Fog::Storage.new(:provider => 'OpenStack')
+        when :volume
+          Fog::Logger.warning("OpenStack[:volume] is not recommended, use Volume[:openstack] for portability")
+          Fog::Volume.new(:provider => 'OpenStack')
         else
           raise ArgumentError, "Unrecognized service: #{key.inspect}"
         end

lib/fog/openstack.rb

@@ -46,6 +46,7 @@ module Fog
     service(:identity, 'openstack/identity', 'Identity')
     service(:network, 'openstack/network', 'Network')
     service(:storage, 'openstack/storage', 'Storage')
+    service(:volume,  'openstack/volume',  'Volume')
 
     # legacy v1.0 style auth
     def self.authenticate_v1(options, connection_options = {})

tests/openstack/volume_tests.rb

@@ -0,0 +1,15 @@
+Shindo.tests('Fog::Volume[:openstack]', ['openstack', 'volume']) do
+
+  volume = Fog::Volume[:openstack]
+
+  tests("Volumes collection") do
+    %w{ volumes }.each do |collection|
+      test("it should respond to #{collection}") { volume.respond_to? collection }
+      test("it should respond to #{collection}.all") { eval("volume.#{collection}").respond_to? 'all' }
+      # not implemented
+      #test("it should respond to #{collection}.get") { eval("volume.#{collection}").respond_to? 'get' }
+    end
+  end
+
+end
+