Add os-client-config to stackforge

os-client-config is a library that consolidates client configuration
for connecting to OpenStack clouds. It wants to be part of an eventual
SDK program, but since that doesn't exist yet, it needs to go into
stackforge.

Change-Id: Icc65ddc6bf4c26e3e8231624d680c3458517fd07
Merge "Add os-client-config to stackforge"