Test 1801 failed on OS X

Hi all,

I created an OS X testbot on Travis CI. Most of the tests passed on it but 1801.
Here are the logs:
clang: https://travis-ci.org/wine-zh/curl/jobs/75475792#L9795
gcc: https://travis-ci.org/wine-zh/curl/jobs/75475795#L9798
I'm not sure is it a bug of curl or due to the system.

I'm newbie here, any help or advice is great appreciated!
Thank you! :-)
