make: fix build when symlinked into GOPATH

In workspace setups that have the source tree symlinked into GOPATH, the `go list `command wouldn't recognize that we're technically within GOPATH, because `pwd` doesn't look like it. For example /home/user/go/src/github.com/ipfs/go-ipfs => /home/user/go/ipfs/go-ipfs produces the import path _/home/user/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-random/random which is not within GOPATH. We get around this by using fully-qualified import paths instead: starting in github.com/ipfs/go-ipfs/ instead of ./ License: MIT Signed-off-by: Lars Gierth <larsg@systemli.org>