Subscribe to systemd on startup

Added code for the implementation of the method
subscribeToSystemdSignals. The reason for this is
because we want to catch the obmc-standby.target
signal and be notified when it is done which means
the BMC is READY.

Change-Id: I824b83676db8cb211f5bee954f98a719a773a62b
Signed-off-by: Josh D. King <jdking@us.ibm.com>
2 files changed