Rename LogDriver to DriverConfig for genericity

The class can be used for both log driver and volume driver specs. Use
a name that reflects this.
Signed-off-by: Joffrey F <joffrey@docker.com>

docker/types/__init__.py

 # flake8: noqa
 from .containers import LogConfig, Ulimit
 from .services import (
-    ContainerSpec, LogDriver, Mount, Resources, RestartPolicy, TaskTemplate,
+    ContainerSpec, DriverConfig, Mount, Resources, RestartPolicy, TaskTemplate,
     UpdateConfig
 )
 from .swarm import SwarmSpec, SwarmExternalCA

docker/types/services.py

@@ -169,7 +169,7 @@ class RestartPolicy(dict):
         self['Window'] = window
 
 
-class LogDriver(dict):
+class DriverConfig(dict):
     def __init__(self, name, options=None):
         self['Name'] = name
         if options: