Refactors set_dependencies

Doing both `go get` and checkout in the same loop made gpm prone
to race conditions - happening when we tried to set versions for
packages at the same time they were being installed.

Having this happening in two different loops makes the approach
more tidy and less prone to error.
Sample godeps file, helps with testing
Superfluous lines
Merge pull request #47 from pote/set-dependencies-refactor

Set dependencies refactor