Correctly report available for ADFS plugin

The ADFS plugin doesn't correctly catch when lxml is not available. This
will fail when a user then tries to iterate all available plugins.

Closes-Bug: #1608169
Change-Id: Ie9d228751306e6df24b43a62392a8f903f82ab82

keystoneauth1/extras/_saml2/__init__.py

@@ -13,6 +13,7 @@
 from keystoneauth1.extras._saml2 import v3
 
 _V3_SAML2_AVAILABLE = v3._SAML2_AVAILABLE
+_V3_ADFS_AVAILABLE = v3._ADFS_AVAILABLE
 
 V3Saml2Password = v3.Saml2Password
 V3ADFSPassword = v3.ADFSPassword

keystoneauth1/extras/_saml2/_loading.py

@@ -44,6 +44,10 @@ class ADFSPassword(loading.BaseFederationLoader):
     def plugin_class(self):
         return _saml2.V3ADFSPassword
 
+    @property
+    def available(self):
+        return _saml2._V3_ADFS_AVAILABLE
+
     def get_options(self):
         options = super(ADFSPassword, self).get_options()
 

keystoneauth1/extras/_saml2/v3/__init__.py

@@ -11,9 +11,11 @@
 # under the License.
 
 from keystoneauth1.extras._saml2.v3 import adfs
+from keystoneauth1.extras._saml2.v3 import base
 from keystoneauth1.extras._saml2.v3 import saml2
 
-_SAML2_AVAILABLE = saml2.etree is not None
+_SAML2_AVAILABLE = base.etree is not None and saml2.etree is not None
+_ADFS_AVAILABLE = base.etree is not None and adfs.etree is not None
 
 Saml2Password = saml2.Password
 ADFSPassword = adfs.Password

keystoneauth1/extras/_saml2/v3/adfs.py

@@ -13,7 +13,11 @@
 import datetime
 import uuid
 
-from lxml import etree
+try:
+    from lxml import etree
+except ImportError:
+    etree = None
+
 from six.moves import urllib
 
 from keystoneauth1 import access

keystoneauth1/extras/_saml2/v3/base.py

@@ -10,7 +10,10 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from lxml import etree
+try:
+    from lxml import etree
+except ImportError:
+    etree = None
 
 from keystoneauth1 import exceptions
 from keystoneauth1.identity import v3