Operate SQLite datastore in WAL mode
Operate SQLite datastore in WAL mode

This should take care of Github issue #472.

google/grr,dunkhong/grr,dunkhong/grr,google/grr,dunkhong/grr,dunkhong/grr,google/grr,dunkhong/grr,dunkhong/grr,google/grr,google/grr,dunkhong/grr,google/grr,google/grr