Fixes the v2 GET /extensions curl example in the documentation.

Change-Id: I2bca0acd4fbc19547be6f5b872ad873938779894
Updated Keystone development install instructions for Ubuntu

Closes-bug:#1205943

Change-Id: I5d18d543126ac4cf8e4fa4d3b2d1f37f9c87e6f8
Merge "Fixes the v2 GET /extensions curl example in the documentation."
Merge "Updated Keystone development install instructions for Ubuntu"