fix(systemd): don't wait until configuration happens
feat(daemon): wait until you get a signal to check for etcd

This is a workaround to daemon-reload and ordering issues. Wait until we
get a NEED_REBOOT signal before checking if etcd is active or not for
the best-effort scheduler.
feat(locksmithctl): get the strategy from update.conf

Get the strategy for the reboot from the update.conf and have systemd
read that file into our environment.
refactor(locksmithctl): set default explicitly
feat(locksmithctl): if etcd is active attempt to unlock

If etcd is active then attempt to unlock any previously held locks. This
will let us cleanup after ourselves if needed.
refactor(locksmitctl): cleanup select for unlockHeldLocks

Based on feedback from Jon clean this up a bit.
refactor(locksmithctl): cleanup waiting logic

More feedback from Jon led to this nice cleanup.
Merge pull request #7 from philips/work-around-daemon-reload

Lots of changes based on chat discussions