Remove integrationtest from DH_GOLANG_EXCLUDES

We should run the integration tests when building the package.

Fixes issue #7.
4 jobs for master in 4 minutes and 55 seconds
Status Job ID Name Coverage
  Build Pkgsrc
passed #7674
build_pkgsrc:stretch

00:00:14

 
  Build Pkg
passed #7675
amd64
build_pkg:stretch:amd64

00:01:13

passed #7676
arm64
build_pkg:stretch:arm64

00:03:58

 
  Upload Pkg
passed #7677
upload_pkg

00:00:40