Use decode on push and pull operations.

Stream helper has the ability to decode the responses from strings to
JSON. This commit enables this functionality on push and pull operations.
Signed-off-by: Aleksandar Topuzovic <aleksandar.topuzovic@gmail.com>

docker/api/image.py

@@ -148,7 +148,7 @@ class ImageApiMixin(object):
         self._raise_for_status(res)
 
     def pull(self, repository, tag=None, stream=False,
-             insecure_registry=False, auth_config=None):
+             insecure_registry=False, auth_config=None, decode=False):
         if insecure_registry:
             warnings.warn(
                 INSECURE_REGISTRY_DEPRECATION_WARNING.format('pull()'),
@@ -200,12 +200,12 @@ class ImageApiMixin(object):
         self._raise_for_status(response)
 
         if stream:
-            return self._stream_helper(response)
+            return self._stream_helper(response, decode=decode)
 
         return self._result(response)
 
     def push(self, repository, tag=None, stream=False,
-             insecure_registry=False):
+             insecure_registry=False, decode=False):
         if insecure_registry:
             warnings.warn(
                 INSECURE_REGISTRY_DEPRECATION_WARNING.format('push()'),
@@ -241,7 +241,7 @@ class ImageApiMixin(object):
         self._raise_for_status(response)
 
         if stream:
-            return self._stream_helper(response)
+            return self._stream_helper(response, decode=decode)
 
         return self._result(response)