Revert "Adds passthrough config for cinder rootwra

This reverts commit 908a9f5dfe.

This config file is empty by default and breaks the ability
to create cinder volumes with the following error from
oslo.rootwrap:

  No section: \'Filters\'\n'

Change-Id: I28c62fedc372c57e86566270b7e1e99b82a921a4
Closes-bug: #1342101

elements/cinder/README.md

@@ -12,25 +12,4 @@ cinder:
   debug: False
     - Print debugging output (set logging level to DEBUG instead of default WARNING level).
   iscsi-helper: tgtadm
-    - Specifies the iSCSI helper to use.  Must match the target element included in the image.
-
-Rootwrap Configuration
-----------------------
-
-It is possible to add custom configuration to the rootwrap.conf used by cinder
-by supplying an ExtraConfig snippet of the following form:
-
-    {
-      "cinder": {
-        "rootwrap_config": [
-          {"section": "SECTIONNAME",
-           "values": [
-              {
-                "option": "OPTIONNAME",
-                "value": "VALUENAME"
-              }
-            ]
-          }
-        ]
-      }
-    }
+    - Specifies the iSCSI helper to use.  Must match the target element included in the image.

elements/cinder/os-apply-config/etc/cinder/rootwrap.d/passthrough.conf

@@ -1,14 +0,0 @@
-{{#cinder}}
-{{#rootwrap_config}}
-[{{{section}}}]
-{{#values}}
-{{#comment}}
-# {{{.}}}
-{{/comment}}
-{{#option}}
-{{{option}}}={{{value}}}
-{{/option}}
-{{/values}}
-
-{{/rootwrap_config}}
-{{/cinder}}