minor: Use virtual_parent for custom fetchers.
minor: Use virtual_parent for custom fetchers.

The distinction here wasn't super meaningful
due to the way we order our "elif" statements,
but we want to reserver "normal_parent" for the
majority of use cases, where you simply tell
the Config what the "foreign_key" is.

rht/zulip,kou/zulip,andersk/zulip,zulip/zulip,eeshangarg/zulip,eeshangarg/zulip,eeshangarg/zulip,eeshangarg/zulip,kou/zulip,zulip/zulip,rht/zulip,kou/zulip,andersk/zulip,andersk/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,rht/zulip,zulip/zulip,andersk/zulip,rht/zulip,zulip/zulip,kou/zulip,rht/zulip,eeshangarg/zulip,rht/zulip,kou/zulip,andersk/zulip,andersk/zulip,zulip/zulip,andersk/zulip,kou/zulip,rht/zulip,kou/zulip