Fix config file path
Fix config file path

Fixes interpretation of config file path so that relative path can
also be used.

Change-Id: I4727402048b22081d014b75a451881fb223301c1
Signed-off-by: Raghuram <000352d18d7e4448d572566798d42a46f2d2e5c3@gmail.com>

opendaylight/spectrometer,opendaylight/spectrometer,opendaylight/spectrometer,opendaylight/spectrometer