speedup grafana install by precompiling go-sqlite3

[Dieterbe]

this:

dieter@dieter-m6800 raintank-docker git diff setup_dev.sh 
diff --git a/setup_dev.sh b/setup_dev.sh
index 9987650..52efa78 100755
--- a/setup_dev.sh
+++ b/setup_dev.sh
@@ -71,4 +71,8 @@ elif [ $MODE == "code" ]; then
        echo "> grafana > grunt"
        grunt

+  echo "> grafana > precompile sqlite3"
+  # avoid sqlite3 recompile every build. significant speedup.
+  find / -name go-sqlite3
+  GOPATH=/opt/raintank/grafana/Godeps/_workspace/ go install -v github.com/mattn/go-sqlite3
 fi

causes:

# github.com/grafana/grafana/pkg/services/sqlstore/migrator
../../grafana/grafana/pkg/services/sqlstore/migrator/migrator.go:10: import /go/src/github.com/raintank/grafana/Godeps/_workspace/pkg/linux_amd64/github.com/mattn/go-sqlite3.a: object is [linux amd64 go1.4 X:precisestack] expected [linux amd64 go1.4.2 X:precisestack]
godep: go exit status 2
[Log] 15-07-06 22:42:56 [ WARN] Fail to execute command [godep go build -o ./bin/grafana-server]

first i noticed one of the scripts was getting go 1.4 instead of 1.4.2, which i fixed,
I then even forced everything on the same go version (dcaed01) but still getting this.