monitor:SIGHUP: Handle reloading JSON config thru SIGHUP

Enable capturing the HUP signal to reload the JSON configuration. This
will reload the appropriate JSON configuration file found and update the
trust groups and fan definitions configured.

Tested:
    JSON configuration is reloaded and updated after SIGHUP
    Single instance of trust groups exist that match the JSON config
    Single instance of fan definitions exist that match the JSON config

Change-Id: If55ca583a67fd76f0733009707bd5c4b5eda3e63
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
5 files changed