[rackspace|compute_v2] updated compute_v2 to get the appropriate endpoint from the service catalog when an endpoint is specified via :rackspace_endpoint with one of the known constants (DFW_ENDPOINT, ORD_ENDPOINT, LON_ENDPOINT); updated compute examples to use rackspace region
[rackspace|compute_v2] fixed chef issue
Merge branch 'master' of github.com:fog/fog into default_endpoint
Merge branch 'master' of github.com:fog/fog into default_endpoint
Merge pull request #1670 from rackspace/default_endpoint

[rackspace|compute_v2] Use endpoint from service catalog rather than constants