Symlink init-keystone into scripts, and use it

os-cloud-config now includes an init-keystone script, replacing the
one shipping in this repository. To make use of it, symlink it into
scripts so it's in the PATH and update the calls to use the new
options, as well as removing the old shell based script to avoid
confusing git and developers.

Change-Id: Ieb2df5fa1dcc51fd42ffa99c9124d2443efac3bf
Merge "Symlink init-keystone into scripts, and use it"