[Merge] ~zhsj/ubuntu/+source/libevent:merge-2.1.12-stable-9 into ubuntu/+source/libevent:debian/experimental

[Shengjing Zhu]

See PPA for test build https://launchpad.net/~zhsj/+archive/ubuntu/libevent/+packages
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https://code.launchpad.net/~zhsj/ubuntu/+source/libevent/+git/libevent/+merge/451102
Your team Ubuntu Sponsors is requested to review the proposed merge of ~zhsj/ubuntu/+source/libevent:merge-2.1.12-stable-9 into ubuntu/+source/libevent:debian/experimental.