Previously the test sets up `LD_LIBRARY_PATH` and `PYTHONPATH`, then runs
Python tests.
Within Python code, setting `sys.path` would achieve the same effect of
setting `PYTHONPATH`. For `LD_LIBRARY_PATH`, it's necessary for C libraries.
But the only C library that cstore depends on is `lz4`, which is supposed to
use the system version. There is no C library provided by this repo -
features like sha1 are compiled in `cstore.so`.
Therefore it's unnecessary to have a separate `.t` file wrapping `.py`
tests. Let's just use `.py` tests directly.
Test Plan:
`./script/unit.py`
Make a temporary change to `cdatapack.c` so it fails unconditionally in
open_datapack. Build the repo in different ways: `make local` and
`python2 setup.py build_clib build_ext`. Then run the test by using
`$HG_CREW/tests/run-tests.py -l test-remotefilelog-datapack.py` without the
`hg-dev` environment and make sure it fails with the expected exception.
Differential Revision: https://phab.mercurial-scm.org/D1429
