Update gopsutil godep dependency. Dont use godep go build anymore

godep seems to have a problem when dependencies have `internal`
packages. So removing `godep go build` and `godep go test` from the
build process in favor of just checking out the correct revisions using
`godep restore` into the regular GOPATH.

This basically means that we are not actually using anything within the
Godeps directory except Godeps.json. I should probably make a separate
go dependency management system that does this.

internal/internal.go

@@ -10,7 +10,7 @@ import (
 
 // Duration just wraps time.Duration
 type Duration struct {
-	time.Duration
+	Duration time.Duration
 }
 
 // UnmarshalTOML parses the duration from the TOML config file