lint: Don't fail until after all files have been checked
lint: Don't fail until after all files have been checked

In order to fail the build on lint errors, we have been exiting
the lint target if `golint` returns a non-zero exit code. This has
the annoying side effect of cancelling the scan when the first lint
error is found. This patch fixes that, so `make lint` will report
all lint errors before exiting with an appropriate code.

LuiseV/quilt,ejj/quilt-dev,quilt/quilt,PenguinToast/quilt,ejj/quilt-dev,mmussomele/quilt,kklin/kelda,NetSys/quilt,kelda/kelda,stevenlin598/quilt,kklin/quilt,kklin/kelda,PenguinToast/quilt,tejasmanohar/quilt,NetSys/quilt,PenguinToast/quilt,kklin/quilt,quilt/quilt,kklin/quilt,NetSys/quilt,quilt/quilt,tejasmanohar/quilt,kklin/kelda,kklin/kelda,kelda/kelda,mmussomele/quilt,LuiseV/quilt,tejasmanohar/quilt,mmussomele/quilt,NetSys/quilt,kayousterhout/quilt,mmussomele/quilt,mmussomele/quilt,tejasmanohar/quilt,ejj/quilt-dev,NetSys/quilt,stevenlin598/quilt,stevenlin598/quilt,stevenlin598/quilt,kayousterhout/quilt,LuiseV/quilt,kelda/kelda,LuiseV/quilt,quilt/quilt,LuiseV/quilt,stevenlin598/quilt,ejj/quilt-dev,PenguinToast/quilt,kayousterhout/quilt,kelda/kelda,mmussomele/quilt,stevenlin598/quilt,PenguinToast/quilt,kayousterhout/quilt,kklin/quilt