Revert "Revert "[rackspace] adding accept headers to block_storage, cdn, compute_v2, databases, identity, load_balancers, storage""

This reverts commit f64e312e92b88e5c5459a97e02064b643facafc5.
[rackspace] fixing merge
Merge pull request #1618 from rackspace/accept_fix

[Rackspace] Fixed Other Service endpoints and added accept headers