x11/bosd: Update to 10.3

Harden the warm-daemon IPC path. Switch the TESTS option to
TESTS_MAKE_ARGS helpers so the port no longer includes
bsd.port.options.mk.

Changelog: https://github.com/FrauBSD/bosd/compare/10.2...10.3

Approved by: fuz (mentor)
Reviewed by: fuz (mentor)
Differential Revision: https://reviews.freebsd.org/D59671