Remove deprecation warnings relating to api-paste

Remove deprecation warnings and backwards compatibility introduced by
commit c355d68a. This commit was introduce in havana and backported to
grizzly. It relates to config options in api-paste.ini.

This commit removes the following deprecated items:
 * cinder.api.auth:CinderKeystoneContext
 * cinder.api.auth:pipeline_factory
 * cinder.api.openstack:FaultWrapper
 * cinder.api.openstack.urlmap:urlmap_factory
 * cinder.api.openstack.volume:APIRouter
 * cinder.api.openstack.volume.versions.Versions
 * cinder.api.sizelimit:RequestBodySizeLimiter

Change-Id: If7c055be0d257dee570da1db4adce2df6e73db14
Update cinder.conf.sample to fix max db conn retries

Another external library change (oslo.db) has broken the gate
because cinder.conf.sample appears to be out of date.  The change
was just to a message string:

   Maximum number of database connection retries during
   startup. Set to -1 to specify an infinite retry count. (integer value)
   ->
   Maximum db connection retries during startup. Set to -1 to
   specify an infinite retry count. (integer value)

This patch updates cinder.conf.sample to get beyond this failure.  The
Cinder team will be talking about how to avoid these issues in the future.

Change-Id: Ia14954842d141b9bd208ce98c5a70a42b014ac45
allow image_id for imageRef in create volume API v2

The create volume request for the V2 API has a property named
"imageRef" with the ID of the image to be used when creating the
volume.
The name of this property is inconsistent as all multi word
properties use snake case and the property in the reponse is named
"image_id".

This adds support for aliasing the imageRef key with image_id when
creating a volume in v2 of the Cinder API in a backward-compatible
way.

Change-Id: I85a5c6734ba05a8a7ea9eff3f849d12fb3d167fb
Closes-Bug: 1375867
Merge "Remove deprecation warnings relating to api-paste"
Merge "allow image_id for imageRef in create volume API v2"