Fog::Model#wait_for: eliminate inner retry loop

AWS frequently takes more than 3 seconds for an instance to appear.
Rather than having the overlapping timeouts for reload and
instance_eval, simply make them both occur with the same timeout.

 + Prevents spurious failures when waiting for AMI
 + Easier to follow flow
[openstack] Retrieve supported API version for Image & Network services
add 2.0.0 to travis build list
Added pointers to provider specific documentation to README.md
Merge pull request #1744 from rackspace/provider_docs

Added pointers to provider specific documentation to README.md
Merge pull request #1699 from frodenas/openstack_get_version

[openstack] Retrieve supported API version for Image & Network services
[cloudstack] add disk_offerings, os_types mock data
[cloudstack] add list_os_types, list_disk_offerings request mocks
[cloudstack] list_os_types, list_disk_offerings request tests, rm pending
Merge pull request #1750 from dm1try/cloudstack_add_list_os_types_and_list_disk_offerings_mocks

[cloudstack] Add list os types and list disk offerings mocks
Merge pull request #1748 from maginatics/timeout2

Fog::Model#wait_for: eliminate inner retry loop
[cloudstack] servers collection, add attributes to :all method
Merge pull request #1754 from dm1try/cloudstack_add_attributes_to_servers_method

[cloudstack] servers collection, add attributes to :all method
Changes the path only if subdomain is not @host

see https://github.com/fog/fog/issues/1631#issuecomment-16396992
Merge pull request #1757 from mhuin/fix_subdomain_check

Changes the path only if subdomain is not @host
AWS | storage: use #service instead of the deprecated #connection in the tests
AWS | storage: add tests for directory#public_url
AWS | storage: add more uniq_id in the tests to avoid collisions
AWS | storage: disabling broken tests
AWS | storage: make directory.persisted? tell the truth

directory.persisted? was relying on the directory having a key which is almost
always true and not related to storage anyways.