dns/c-ares: update 1.11.0 -> 1.12.0

• see https://daniel.haxx.se/blog/2016/10/14/a-single-byte-write-opened-a-root-execution-exploit/ for a nice writeup of the CVE.

PR: 213495
MFH: r424257
Changes: https://c-ares.haxx.se/changelog.html
Security: CVE-2016-5180
Approved by: zi (maintainer)
Approved by: ports-secteam (feld)