Allow content type specification in resource.patch (#174)

For Custom Resource Definitions, the strategic merge type will fail
with "strategic merge patch format is not supported".

Allow the override of content type when patching so that all three
patch merge types are individually choosable - this means that
JSON Merge Patch operations can be chosen for certain operations

Author: willthames

openshift/dynamic/client.py

@@ -185,11 +185,9 @@ def patch(self, resource, body=None, name=None, namespace=None, **kwargs):
         if resource.namespaced:
             namespace = self.ensure_namespace(resource, namespace, body)
 
+        content_type = kwargs.pop('content_type', 'application/strategic-merge-patch+json')
         path = resource.path(name=name, namespace=namespace, **kwargs)
 
-        content_type = self.client.\
-            select_header_content_type(['application/json-patch+json', 'application/merge-patch+json', 'application/strategic-merge-patch+json'])
-
         return self.request('patch', path, body=body, content_type=content_type)