presence: Enable use of alternate json config file

Set the location and file for an alternate json config file that would
be used in place of the default if it exists.

Tested:
    Default config used when alternate does not exist
    Alternate config used when present

Change-Id: I79ac24f261776a60edff949598aea0be97e64bbe
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
1 file changed