[vsphere|compute] add list_templates function

Templates used to be included in Compute[:vsphere].servers.all, but
they've been pruned out for awhile now.  This patch adds the
functionality back in so that templates may be located for cloning.

lib/fog/vsphere/compute.rb

@@ -49,6 +49,8 @@ module Fog
       request :get_network
       request :list_datastores
       request :get_datastore
+      request :list_templates
+      request :get_template
       request :get_folder
       request :list_folders
       request :create_vm

lib/fog/vsphere/requests/compute/list_templates.rb

@@ -0,0 +1,50 @@
+module Fog
+  module Compute
+    class Vsphere
+      class Real
+        def list_templates(options = { })
+          
+          options[:folder] ||= options['folder']
+          if options[:folder] then
+            list_all_templates_in_folder(options[:folder], options[:datacenter])
+          else
+            list_all_templates(options)
+          end
+        end
+        
+        private
+        
+        def list_all_templates_in_folder(path, datacenter_name)
+          folder = get_raw_vmfolder(path, datacenter_name)
+
+          vms = folder.children.grep(RbVmomi::VIM::VirtualMachine)
+          # remove all virtual machines that are not template
+          vms.delete_if { |v| not v.config.template }
+          
+          vms.map(&method(:convert_vm_mob_ref_to_attr_hash))
+        end
+        
+        def list_all_templates(options = {})
+          datacenters = find_datacenters(options[:datacenter])
+
+          vms = datacenters.map do |dc|
+            @connection.serviceContent.viewManager.CreateContainerView({
+              :container  => dc.vmFolder,
+              :type       =>  ["VirtualMachine"],
+              :recursive  => true
+            }).view
+          end.flatten
+          # remove all virtual machines that are not templates
+          vms.delete_if { |v| not v.config.template }
+
+          vms.map(&method(:convert_vm_mob_ref_to_attr_hash))
+        end
+
+      end
+      class Mock
+        def list_templates(filters = { })
+        end
+      end
+    end
+  end
+end

lib/fog/vsphere/requests/compute/list_virtual_machines.rb

@@ -22,7 +22,11 @@ module Fog
         def list_all_virtual_machines_in_folder(path, datacenter_name)
           folder = get_raw_vmfolder(path, datacenter_name)
 
-          folder.children.grep(RbVmomi::VIM::VirtualMachine).map(&method(:convert_vm_mob_ref_to_attr_hash))
+          vms = folder.children.grep(RbVmomi::VIM::VirtualMachine)
+          # remove all template based virtual machines
+          vms.delete_if { |v| v.config.template }
+          
+          vms.map(&method(:convert_vm_mob_ref_to_attr_hash))
         end
 
         def list_all_virtual_machines(options = { })