Upgrade to ubuntu:trusty-20190515 (#63468)
Summary:
Security Upgrade to ubuntu:trusty-20190515
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63468
Reviewed By: ngimel
Differential Revision: D31393552
Pulled By: malfet
fbshipit-source-id: 4e2399e3cddc1d549c08c82c08015e00569c19bc
