Null out lock vars so that __del__ gets called
Null out lock vars so that __del__ gets called

The builder was holding lock variables in the loop which means that
sometimes a state.Lock object would be created for the same file-id
twice, triggering the assertion. Assign the lock variables to None to
ensure that the state.Lock objects are destroyed before creating the
next one in the loop.

apenwarr/redo,apenwarr/redo,apenwarr/redo,apenwarr/redo