Force init to always fetch from the network

[F21]

It would be nice if there is an option to force init to fetch from the network.

In my case, I might have dependencies on libraries that I might have in my GOPATH I've previously submitted some patches to. My work flow for submitting patches to Go projects is to:

• Create $GOPATH/src/projectowner/projectrepo
• Exec git add remote fork github.com/F21/myfork.

Because these already exist in my GOPATH, dep will currently use my outdated/in progress fork. In some cases, if I create a branch on my fork, push it and did not checkout master, dep will set that branch as the version.

[sdboyer]

Totally reasonable request, sure. We definitely want to add more modes to init - e.g. reading just from the network, doing interactive prompting, importing from existing tooling. It's on my TODO list to do a bigger writeup of that requirement.

[sdboyer]

Closing this in favor of #186, as that issue encompasses this one.