Make `wipe-openstack` correctly reset all services.

The boot-stack element contains a utility, wipe-openstack,
which clears all openstack databases, and restarts all services.

Before this change, wipe-openstack would not complete sucessfully
when run again after the first time, due to some networking config
and service restarts not being fully idempotent.

This change causes wipe-openstack to work as intended, and renames
reset-keystone, reset-nova, etc. to init-*, to better capture their
purposes.

Change-Id: I8aeca8b21201cf12bcd1c9e6b97dc61a7b102921