IBM Storwize: Improve error message

Message "Unable to retype: Volume is replicated." can not really reflect
the reason why retype failed. We need to add additional information to
help user to better understand why retype failed.

Change-Id: If68bb1ba1e72df46fef35394c9ad207ffdeb271b
Switch to oslo.serialization

Very simple import change in each file, just touches a whole
lot of files. jsonutils has graduated into a standalone library
and has been removed from the oslo-incubator repository.
We should be using the library for all projects.
This commit doesn't change files synced from oslo-incubator, and
doesn't remove the 'module=jsonutils' in openstack-common.conf.
Another sync commit will cover that.

Change-Id: I56ea380a85e8a3c1b42b2425430fc28409937365
Implementing the use of _L’x’/i18n markers

Placing the _Lx markers back into the code.  No other cleaner solution has
has been implemented. Patches will be submitted in a series of sub
directories and in a fashion that is manageable.
This is the sixth commit of this kind

Partial-Bug: #1384312

Change-Id: I42b4e168deec9930571c1869fe1a181d4aad1112
Merge "Switch to oslo.serialization"
Merge "IBM Storwize: Improve error message"
Merge "Implementing the use of _L’x’/i18n markers"