need modify `runtest.py` parts of the document

[Jeho, Sung]

see intro/contributing/#running-django-s-test-suite-for-the-first-time

Now we are ready to run the test suite. If you’re using GNU/Linux, Mac OS X or some other flavor of Unix, run:
$ ./runtests.py

If follow this command, then you'll see:

(django-devel) jehos@class:/tmp/django/tests⟫ ./runtests.py
Traceback (most recent call last):
  File "./runtests.py", line 22, in <module>
    from django.utils.deprecation import (
ImportError: cannot import name 'RemovedInDjango21Warning'

It should be changed as follows.

$ PYTHONPATH=..:$PYTHONPATH ./runtests.py

[Tim Graham]

Based on the error, it looks like you missed this step: pip install -e /path/to/your/local/clone/django/.

[Jeho, Sung]

Replying to Tim Graham:

Based on the error, it looks like you missed this step: pip install -e /path/to/your/local/clone/django/.

sorry, i missing that sequence.
thank you.