Replaces exception re-raising in Hyper-V

In a few cases in the Hyper-V driver classes, generic exceptions
are getting caught, logged and a domain specific exception is raised.

This creates issues in identifying the exception cause programmatically
(e.g. in unit tests).

This patch enforces the usage of excutils.save_and_reraise_exception()

Closes-Bug: #1280363

(cherry-picked from commit 80ffc9b8b38293c05c9d48cb615b24fd7255a850)

Change-Id: I27cc54941c5f592ea567ccaa8fa369362da1427f
Added missing raise statement when checking the config driver format

Closes-bug: #1275772

(cherry-picked from commit 378c28a8c05d3943324b5a39edef947ed7a9f52a)

Change-Id: I636525d0272511d4192c43d18c56e867fb7514d8