build: go get goveralls
build: go get goveralls

We were missing goveralls and Travis wasn't even telling us of the
error. Bad Travis, bad!

Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@intel.com>

clearcontainers/proxy,dlespiau/proxy,dlespiau/clearcontainers-proxy,clearcontainers/proxy,dlespiau/clearcontainers-proxy,dlespiau/proxy