Bug#1077946: can't find gogo/protobuf/proto

[Rebecca N. Palmer]

Control: tags -1 patch

That is in golang-github-gogo-protobuf-dev, which was installed for the 
buildd build (successful) but not for recent reproducible-builds 
attempts (failed).  Probably it used to be installed because some other 
build-dependency was using it, but that package then switched to 
golang-google-protobuf-dev while this still needs the other version.

Hence, adding golang-github-gogo-protobuf-dev to this package's own 
build dependencies will probably fix this.  (I haven't tried this.)