Replaced hard-coded uri to discovered uri for GET/PUT in occlient.cpp

Replaced hard-coded uri to discovered uri for GET/PUT in occlient.cpp

occlient.cpp always made GET PUT requests on /a/light as ocserver was
built with /a/light.
Changed this to make requests to discovered resources to enable easier
testing for test engineers.

Change-Id: I642b1d83e46f91d92270d414dda933b6cf97240e
Signed-off-by: Mandeep Shetty <mandeep.shetty@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2721
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>