Specs for existing `Fog::Bin` interface

Prepartion for fog/fog-core#105
Detailed checks for `Brightbox` class
Mark additional DigitalOcean test as pending

See: https://github.com/fog/fog/pull/3304
Disable ALL DigitalOcean tests until fixed

There appears to be a glitch in the test suite such that running
`bundle exec rake travis` passes locally without executing the DO tests
but they are running on Travis itself.

So fed up playing whackamole with failures. They are off until the
broken code is fixed.

See https://github.com/fog/fog/pull/3304

This reverts commit 9b7b8fd49000d6ccb82bf2a731b78d6974977e67.
This reverts commit fa9254ba8ddba408617553f0a877bdea64ec80d5.
Merge branch 'master' into 105_provider_registration
Remove Rackspace references until reinstated

Tests were based on v1.25.0 which included Rackspace support. It was
extracted into a module and not correctly referenced so is no longer
present on master.

This commit should be reverted and the specs passing before the next
release.
Merge pull request #3326 from fog/105_provider_registration

Add specs for existing `Fog::Bin` API