Added test for failure to allocate ip on fully allocated subnet.
Added test for failure to allocate ip on fully allocated subnet.

roaet/quark,insequent/quark,roaet/quark,Cerberus98/quark,rackerlabs/quark,blamarvt/quark,lmaycotte/quark,Cerberus98/quark,asadoughi/quark,rackerlabs/quark,alanquillin/quark,alanquillin/quark,asadoughi/quark,insequent/quark,jkoelker/quark,lmaycotte/quark