Fixed impossible Schemata
Fixed impossible Schemata

parent_role_id NEEDS to be allowed to be NULL, because otherwise a first role can never be inserted.
bakura10/zfc-rbac,Ocramius/zfc-rbac,bakura10/zfc-rbac,svycka/zfc-rbac,Ocramius/zfc-rbac,Orkin/zfc-rbac,ZF-Commons/zfc-rbac,ZF-Commons/zfc-rbac,Orkin/zfc-rbac,svycka/zfc-rbac,Alexandre-T/zfc-rbac,Alexandre-T/zfc-rbac