Merge pull request #44 from verizonlabs/build-on-osx

If we're on OS X then have Go cross compile for us

build.sh

@@ -1,6 +1,10 @@
 #!/usr/bin/env bash
 set -e
 
+if [ "$(uname)" == "Darwin" ]; then
+	export GOOS=linux
+fi
+
 ORG_PATH="github.com/containernetworking"
 export REPO_PATH="${ORG_PATH}/plugins"