Sync the latest loopingcall module from oslo-incubator

We have not done a sync of loopingcall since its dependency
upon the old i18n module was removed.  To get that old code
removed we need to do this sync.

Current HEAD in OSLO:
---------------------
commit 36b0e8570b449129d6d474c03b02ceb62edb78df
Date:   Thu Dec 11 11:27:08 2014 +0100
We shouldn't replace `oslo-incubator` in comments

Change being merged with this patch:
---------------------
5d40e143 -  Remove code that moved to oslo.i18n

Change-Id: I2fd9cb73cf347adfb2ce203e45d5059604ed5f7a
Handle the volume not found case in the VMAX driver

When a volume cannot be found on the array, VMAX driver throws
an exception. This brings a volume into error_deleting state during
the volume deletion operation. This patch fixed it by returning None
when a volume cannot be found.

Closes-Bug: #1395830
Change-Id: Iad714ff6e577bc9d7cf69b8654a7eb726969279e
Expand the description of extra_capabilities

The existing description of extra_capabilities was a bit terse,
meaning deployers couldn't easily gauge the power of this option.
This patch expands the textual description using information from
the blueprint and original commit message, so it can be picked
up automatically by the documentation.

Change-Id: Iac2b6d8a3ce4875a8c1d9874dd7f0e4cf7c435c0
Closes-Bug: 1288044
Merge "Expand the description of extra_capabilities"
Merge "Handle the volume not found case in the VMAX driver"
Merge "Sync the latest loopingcall module from oslo-incubator"