[rackspace|identity] Handle non-array responses from list calls.

lib/fog/rackspace/requests/identity/list_credentials.rb

@@ -3,11 +3,18 @@ module Fog
     class Identity
       class Real
         def list_credentials(user_id)
-          request(
+          response = request(
             :expects => [200, 203],
             :method => 'GET',
             :path => "users/#{user_id}/OS-KSADM/credentials"
           )
+
+          if response.body.include? 'credential'
+            response.body['credentials'] = [response.body['credential']]
+            response.body.delete('credential')
+          end
+
+          response
         end
       end
     end

lib/fog/rackspace/requests/identity/list_tenants.rb

@@ -3,11 +3,18 @@ module Fog
     class Identity
       class Real
         def list_tenants()
-          request(
+          response = request(
             :expects => [200, 203],
             :method => 'GET',
             :path => 'tenants'
           )
+
+          if response.body.include? 'tenant'
+            response.body['tenants'] = [response.body['tenant']]
+            response.body.delete('tenant')
+          end
+
+          response
         end
       end
     end

lib/fog/rackspace/requests/identity/list_user_roles.rb

@@ -3,11 +3,18 @@ module Fog
     class Identity
       class Real
         def list_user_roles(user_id)
-          request(
+          response = request(
             :expects => [200, 203],
             :method => 'GET',
             :path => "users/#{user_id}/roles"
           )
+
+          if response.body.include? 'role'
+            response.body['roles'] = [response.body['role']]
+            response.body.delete('role')
+          end
+
+          response
         end
       end
     end

lib/fog/rackspace/requests/identity/list_users.rb

@@ -3,11 +3,18 @@ module Fog
     class Identity
       class Real
         def list_users()
-          request(
+          response = request(
             :expects => [200, 203],
             :method => 'GET',
             :path => 'users'
           )
+
+          if response.body.include? 'user'
+            response.body['users'] = [response.body['user']]
+            response.body.delete('user')
+          end
+
+          response
         end
       end
     end