MFH: r487282

Security update to 4.8.4

Addresses three security advisories: PMASA-2018-06, PMASA-2018-07,
PMASA-2018-08.

Also includes additional non-security related code updates.

ChangeLog: https://www.phpmyadmin.net/files/4.8.4/

PR: 233953
Security: ed10ed3f-fddc-11e8-94cf-6805ca0b3d42

Approved by: ports-secteam (miwi)