Move services to fog-core

These services were missed in the initial work.
Remove duplicate requires from services

Following work on reorganising the requires, there was an inconsistent
approach to where service wrappers are required. (Fog::Compute...)

Since they should be standardised and shared across providers (although
they really aren't yet) they have been moved to `fog-core` gem.

Each provider has their own `lib/fog/{provider}/core` files that is
required by each of their services. These files should all require
`fog/core` which already required most or these.

So this removes the extra cases to concentrate them in core.
Fixing [excon][WARNING] Invalid Excon request keys log noise when trying to use STS
[core] Use fog-core v1.21.0

Rather than tracking the Github repo, this references the gem directly.

Locally seeing an issue with 1.8.7 / unf gem test which surprised not
seeing on Travis.
Merge pull request #2671 from fog/use_core_gem

[core] Use fog-core v1.21.0
Merge pull request #2670 from fog/remove_remaining_services

[core] Remove remaining services
Exclude the duplicated Ruby v2.1.0 run

We only run coverage on 2.1.0 but due to the testing matrix we actually
run the same tests twice.

Hopefully this removes the run without coverage.
Remove testing for 1.9.2

Never seen any differences/issues between 1.9.2 and 1.9.3 and I guess it
isn't the most used version.

This way we free up a Travis box for someone else.
Exclude the duplicated Ruby v2.1.0 run (v2)

We only run coverage on 2.1.0 but due to the testing matrix we actually
run the same tests twice.

Hopefully this removes the run without coverage (since the last one was
the wrong version).
Merge pull request #2669 from joshgarnett/master

Fixing [excon][WARNING] Invalid Excon request keys log noise when trying...
Added find_by_name to openstack identity-users model and tests
simplify travis.yml to just use explicit includes
Merge pull request #2672 from fog/reduce_ci_burden

Reduce Travis CI burden
Merge pull request #1956 from ProGEEK/vnc_mouse_fix

Added tablet device to libvirt template to fix VNC and Mouse pointer
Incorrectly requiring all of fog here
Merge pull request #2676 from fog/extract_archive_bad_require

[Rackspace] Incorrectly requiring all of fog for Fog::Storage.new
Merge pull request #2 from grossjo/rage4_dns_support

Rage4 dns support
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of github.com:grossjo/fog
remove add nils and remove array merge