devel/opengrok: Upgrade to version 1.7.31

Upgrade opengrok to the latest upstream version to fix CVE-2021-2322,
which was actually fixed upstream in 1.6.7.

Convert the wrapper script from /bin/csh to /bin/sh.

Jave 11+ is required.

PR: 260534
MFH: 2022Q2
Security: 1135e939-62b4-11ec-b8e2-1c1b0d9ea7e6