check-code: drop the camelcase checks
Fro about 2 years we have been using CamelCase is class names. That rules gets
in the way of assigning class or exception in compatibility layers.
I think it is safe to drop it now that we started using CamelCase for some case.
My motivation for this is the need to assign `FileNotFoundError` in `pycompat`.
Differential Revision: https://phab.mercurial-scm.org/D11309
#require serve
$ hg clone http://localhost:$HGPORT/ copy
abort: * (glob)
[100]
$ test -d copy
[1]
$ "$PYTHON" "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid
$ cat dumb.pid >> $DAEMON_PIDS
$ hg clone http://localhost:$HGPORT/foo copy2
abort: HTTP Error 404: * (glob)
[100]
$ killdaemons.py