Previously we updated the file mtimes if the file has not been seen
before - i.e on the first iteration of the loop.
If the mtime has been changed we triggered the notify_file_changed()
method which in all cases except the translations will result in the
process being terminated. To be strictly correct we need to update the
mtime for either branch of the conditional.
Regression in 6754bffa2b2df15a741008aa611c1bb0e8dff22b.