Remove -u flag from got get

This breaks GAE applications that use go, and libraries that use app engine dependencies that are stored in the appengine GOROOT.


You get errors like this:

```
>> Getting package github.com/smartystreets/goconvey
>> Getting package github.com/jacobsa/oglematchers
>> Getting package github.com/mjibson/goon
>> Setting github.com/jacobsa/oglematchers to version 4fc24f97b5b74022c2a3f4ca7eed57ca29083d3e
package github.com/mjibson/goon
        imports code.google.com/p/goprotobuf/proto: directory "/home/mark/go_appengine/goroot/src/pkg/code.google.com/p/goprotobuf/proto" is not using a known version control system
>> Setting github.com/smartystreets/goconvey to version 13db5bb88b509cb5ac23c1e8624a0ab9e685e083
>> All Done
```

Let me know if this will break other things, maybe there is an alternate workaround for this issue.