Remove unused dumps validation in JsonParam value
Remove unused dumps validation in JsonParam value

If the passed parameter is not a valid Json object, a ValueError
exception will be raised in JsonParam parse(). So no need this dumps
validation in value().

Change-Id: Ie450d3923a905b7de3dcbece351aec937ebe7a61

srznew/heat,cwolferh/heat-scratch,dims/heat,rh-s/heat,NeCTAR-RC/heat,rdo-management/heat,dims/heat,miguelgrinberg/heat,NeCTAR-RC/heat,cryptickp/heat,pratikmallya/heat,gonzolino/heat,miguelgrinberg/heat,steveb/heat,noironetworks/heat,rdo-management/heat,gonzolino/heat,maestro-hybrid-cloud/heat,cryptickp/heat,redhat-openstack/heat,ntt-sic/heat,srznew/heat,jasondunsmore/heat,dragorosson/heat,noironetworks/heat,takeshineshiro/heat,openstack/heat,redhat-openstack/heat,ntt-sic/heat,pshchelo/heat,pshchelo/heat,dragorosson/heat,maestro-hybrid-cloud/heat,jasondunsmore/heat,rh-s/heat,cwolferh/heat-scratch,takeshineshiro/heat,steveb/heat,pratikmallya/heat,openstack/heat