API: Fix logic for list=recentchanges prop=userid

When prop=userid is requested, we need the rc_user field; when prop=user
is requested, we need both rc_user and rc_user_text.

But for some reason when only prop=userid is requested the code is
requesting only rc_user_text and not rc_user. Fix that.

Bug: 62301
Change-Id: I86f1f35ebd18e45335cdf43ab3ba0a3e9b0e06b4
Merge "API: Fix logic for list=recentchanges prop=userid"