filectx: fix return of renamed
How is this not blowing up everywhere?
It seems that filelog.renamed has always returned False (incorrectly a
boolean) instead of the assumed None. Tracing through history, you need
to skip over my move of code in 2013 by annotating from 896193a9cab4^
and you can see the original code is from 2007 (180a3eee4b75) and that
ab9fa7a85dd9 broke this by assuming renamed was a bool (instead of
Refactoring memctx code later exposed this bug.