please build hockeypuck on every architecture

[Matthias Klose]

please build hockeypuck on every architecture, afaics it builds at least on armhf.

when built with gccgo it fails:

make[1]: Entering directory '/home/doko/tmp/hockeypuck-1.0~rel20140413+7a1892a~trusty.1'
GOPATH=/home/doko/tmp/hockeypuck-1.0~rel20140413+7a1892a~trusty.1/build go install -ldflags "-X github.com/hockeypuck/hockeypuck.Version 1.0~rel20140413+7a1892a~trusty.1" github.com/hockeypuck/hockeypuck/cmd/hockeypuck
# github.com/hockeypuck/hockeypuck/openpgp
build/src/github.com/hockeypuck/hockeypuck/openpgp/add.go:253:6: error: 'signable' declared and not used
  var signable PacketRecord
      ^
Makefile:9: recipe for target 'compile' failed
make[1]: *** [compile] Error 2

I didn't check if this is Go 1.4 or gccgo related.