button-handler: Add reset button actions

Creates a signal handler for the 'Released' signal.

This will reboot the host if it is powered on.  If the
system is off, it won't do anything.

As with the other buttons, it only installs the watch if
the button object exists.

Tested: Used the 'simPress' method on the reset object
        to trigger the signal.

Change-Id: I4102cd8c260d07afb018b2c186e78a768e642a18
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
2 files changed