bpo-29686: Changed case.shortDescription to return empty string instead of None

[viniciusd]

http://bugs.python.org/issue29686

[the-knights-who-say-ni]

Hello, and thanks for your contribution!

I'm a bot set up to make sure that the project can legally accept your contribution by verifying you have signed the PSF contributor agreement (CLA).

Unfortunately our records indicate you have not signed the CLA. For legal reasons we need you to sign this before we can look at your contribution. Please follow these steps to rectify the issue:

1. Sign the PSF contributor agreement. The "bugs.python.org username" requested by the form is the "Login name" field in "Your Details" at b.p.o
2. Wait at least one US business day and then check the "Contributor form received entry under "Your Details" on bugs.python.org to see if your account has been marked as having signed the CLA (the delay is due to a person having to manually check your signed CLA)
3. Reply here saying you have completed the above steps

Thanks again to your contribution and we look forward to looking at it!

[mention-bot]

@viniciusd, thanks for your PR! By analyzing the history of the files in this pull request, we identified @berkerpeksag, @gvanrossum, @tim-one, @vadmium and @mdickinson to be potential reviewers.

[berkerpeksag]

Closing this since bpo-29686 has been rejected. Thanks for the PR!