New port, devel/rubygem-fog-json102: Copied from devel/rubygem-fog-json

This new port was necessary because net/rubygem-fog-openstack pulls in two
conflicting versions of the fog-core gem (version 1 via
devel/rubygem-fog-core1 and version 2 via devel/rubygem-fog-json ->
devel/rubygem-fog-core).