Adds verfication for Bootable Volume

This submission is to verify the response body of Bootable Volume.
To do so, added required assertions in "test_volumes_get.py"
test script located at ./api/volume and also required modifications
are done in get_volume, list_volumes, list_volumes_with_detail
methods of volumes_client.py(XML)

Implements blueprint: cinder-grizzly1-blueprints-implementation

Change-Id: Id8ac81e268abde1df8d11055079e13e67d4e7ae1
diff --git a/tempest/api/volume/test_volumes_get.py b/tempest/api/volume/test_volumes_get.py
index 2e90f16..e5e350e 100644
--- a/tempest/api/volume/test_volumes_get.py
+++ b/tempest/api/volume/test_volumes_get.py
@@ -68,6 +68,10 @@
                          fetched_volume['metadata'],
                          'The fetched Volume is different '
                          'from the created Volume')
+        if 'imageRef' in kwargs:
+            self.assertEqual(fetched_volume['bootable'], True)
+        if 'imageRef' not in kwargs:
+            self.assertEqual(fetched_volume['bootable'], False)
 
     @attr(type='gate')
     def test_volume_get_metadata_none(self):
diff --git a/tempest/services/volume/xml/volumes_client.py b/tempest/services/volume/xml/volumes_client.py
index 936e036..49cbe28 100644
--- a/tempest/services/volume/xml/volumes_client.py
+++ b/tempest/services/volume/xml/volumes_client.py
@@ -60,6 +60,21 @@
         """Return the element 'attachment' from input volumes."""
         return volume['attachments']['attachment']
 
+    def _check_if_bootable(self, volume):
+        """
+        Check if the volume is bootable, also change the value
+        of 'bootable' from string to boolean.
+        """
+        if volume['bootable'] == 'True':
+            volume['bootable'] = True
+        elif volume['bootable'] == 'False':
+            volume['bootable'] = False
+        else:
+            raise ValueError(
+                'bootable flag is supposed to be either True or False,'
+                'it is %s' % volume['bootable'])
+        return volume
+
     def list_volumes(self, params=None):
         """List all the volumes created."""
         url = 'volumes'
@@ -72,6 +87,8 @@
         volumes = []
         if body is not None:
             volumes += [self._parse_volume(vol) for vol in list(body)]
+        for v in volumes:
+            v = self._check_if_bootable(v)
         return resp, volumes
 
     def list_volumes_with_detail(self, params=None):
@@ -86,14 +103,17 @@
         volumes = []
         if body is not None:
             volumes += [self._parse_volume(vol) for vol in list(body)]
+        for v in volumes:
+            v = self._check_if_bootable(v)
         return resp, volumes
 
     def get_volume(self, volume_id):
         """Returns the details of a single volume."""
         url = "volumes/%s" % str(volume_id)
         resp, body = self.get(url, self.headers)
-        body = etree.fromstring(body)
-        return resp, self._parse_volume(body)
+        body = self._parse_volume(etree.fromstring(body))
+        body = self._check_if_bootable(body)
+        return resp, body
 
     def create_volume(self, size, **kwargs):
         """Creates a new Volume.