Revert 9f3f532

remove_error is not useful because the error file is created on the submit
host anyway, and it has a different name on the execution host.
https://lists.cs.wisc.edu/archive/htcondor-users/2013-May/msg00063.shtml

So we probably need to use a DAG 'SCRIPT POST' to delete unused error files.

TODO: look at stream_error as well.