Move volume parsing to config.types module

This removes the last of the old service.ConfigError

Signed-off-by: Daniel Nephin <dnephin@docker.com>

tests/integration/resilience_test.py

@@ -3,13 +3,17 @@ from __future__ import unicode_literals
 
 from .. import mock
 from .testcases import DockerClientTestCase
+from compose.config.types import VolumeSpec
 from compose.project import Project
 from compose.service import ConvergenceStrategy
 
 
 class ResilienceTest(DockerClientTestCase):
     def setUp(self):
-        self.db = self.create_service('db', volumes=['/var/db'], command='top')
+        self.db = self.create_service(
+            'db',
+            volumes=[VolumeSpec.parse('/var/db')],
+            command='top')
         self.project = Project('composetest', [self.db], self.client)
 
         container = self.db.create_container()