upstream commit

don't record duplicate LocalForward and RemoteForward
 entries; fixes failure with ExitOnForwardFailure+hostname canonicalisation
 where the same forwards are added on the second pass through the
 configuration file. bz#2562; ok dtucker@

Upstream-ID: 40a51d68b6300f1cc61deecdb7d4847b8b7b0de1
