Ignore snapshot parent mappings in import
Ignore snapshot parent mappings in import

Parent objects for snapshots (currently only Audit) need to be ignored
in the mapping column handler. The column handler will in these cases
stay for an export only purpose.

AleksNeStu/ggrc-core,AleksNeStu/ggrc-core,VinnieJohns/ggrc-core,VinnieJohns/ggrc-core,VinnieJohns/ggrc-core,plamut/ggrc-core,plamut/ggrc-core,AleksNeStu/ggrc-core,plamut/ggrc-core,plamut/ggrc-core,VinnieJohns/ggrc-core,AleksNeStu/ggrc-core