Fix a few Sphinx warnings

Corrects some rst formatting to eliminate warnings in
the documenation build.

Change-Id: I4026a1c8e7fae1928ca50d80aa1b5440faf754da
Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>
Handle errors raised by extend_volume

Errors raised by extend_volume aren't handled by the manager.
This means the volume status will not be updated to 'error_extending'
when an error is raised during the process.

* Handle such errors and update volume status accordingly
* Add logging for the extend volume process

Fixes: bug #1199471
Change-Id: I06a037af0344d1eaf4115f0af5a85ceeab1ffd37
Merge "Fix a few Sphinx warnings"
Merge "Handle errors raised by extend_volume"