Fix LT-14979 bad lexical relations imported

Since we have exported the 'default' lexical relations in our ranges
and they aren't real, we created bad LexRefType objects on import

* lexical-relations with no guid or parent no longer rate a LexRefType
* Stopped writing out useless ranges for unused lexical-relations

Change-Id: I49270bba40934e3a2d5a352a4b2d099c945b9439