Update to 8.7.17

Changelog: https://typo3.org/article/typo3-931-8717-and-7630-security-releases-published/

PR: 229836
Submitted by: Helmut Ritter <freebsd-ports@charlieroot.de> (maintainer)
MFH: 2018Q3
Security: Helmut Ritter <freebsd-ports@charlieroot.de>