[GH-2706] Update ruby-libvirt dependency to 0.5

Also removed guard related to JRuby since the important part is opting
into lib-virt
[rackspace|compute_v2] adds virtual interfaces support
Merge branch 'master' of github.com:fog/fog into virtual_interfaces
[google] Don't swallow google errors in images.get

Catch and raise only Fog::Errors::NotFound
Fix mock, images.get now returns a 404 if image does not exist
Merge pull request #2728 from rackspace/virtual_interfaces

[rackspace|compute_v2] add virtual interface support.
Merge pull request #2720 from fog/2706_bump_libvirt

[GH-2706] Update ruby-libvirt dependency to 0.5
Rename testing class to fit filename

`TestFogXMLConnection` didn't really match with the file name of
`test/fog/xml/connection_test.rb` due to the namespacing and placement
of "Test"
Merge pull request #2745 from maestrodev/google-image-notfound

[google|compute] Don't swallow google errors in images.get
[DigitalOcean] Skip consistently timing out tests

The server tests in digital ocean have been frequently timing out.

* https://travis-ci.org/fog/fog/jobs/20605301#L1030
* https://travis-ci.org/fog/fog/jobs/19765753#L1233
...and many more

Each timeout run wastes Travis resources and the time of the people who
have to check why their unrelated changes are failed.

We've even become so complacent about it, standard practice is to just
comment and merge.

So I'm disabling the tests until someone fixes it or we replace the
server tests with a cleaner approach, whichever comes first.
[rackspace|compute_v2] removing hard coded timeout in servers
Merge pull request #2753 from fog/disable_digital_ocean_test_fail

[DigitalOcean] Skip consistently timing out tests
bump rbovirt dependency
Merge pull request #2756 from rackspace/remove_timeout

[rackspace|compute_v2] removing hard coded timeout in servers