Fix an exception handling issue in con-client app.

Fix an exception handling issue in con-client app.

Though con-client app do not discover configuration,
diagnostics, and factorySet collection resources in
a network, the con-client app can be proceded.
And even when a response for any GET/PUT request indicates
a bad request, it is correctly delivered to the app.

Reference issue ID : [IOT-291]

Change-Id: Ic101013daa6efea9639295553022fd67f58c925e
Signed-off-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/271
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>