add repo alias for speter.net glide dependency

[jackfrancis]

See this commit for an example:

deis/workflow-manager@73f5df2

[arschles]

Upon further inspection, this repository doesn't have any transitive dependencies to the dependency in question (speter.net/go/exp/math/dec/inf). I verified by executing the following commands on the master branch of this repo:

rm -rf vendor
glide install

... and no errors occurred. Also, the glide.lock doesn't mention this dependency. If this does become a problem in the future, simply add an alias like in the workflow-manager glide.yaml file.