dns/dnsdist: 0.0.281gade4ced -> 0.0.336gc278ffd

• Also add maintainer mirror and LOCAL as a fallback. Upstream only seems to keep the last 50 distfiles on their mirrors and this has broken fetch in the past (see bug 203613).

PR: 204113
Submitted by: Carlos J Puga Medina <cpm@fbsd.es> (maintainer)