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 test-repo jshint hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run jshint on all tracked files ending in .js except vendored dependencies
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.js' \
> 2>/dev/null \
> | xargs jshint