Revert "Merge pull request #33 from square/reloading-keystore"

Reverting temporarily for downstream dependencies. Will revert the
revert once those are fixed up.

This reverts commit d6b0532b76cf6180eda5055ddbc8e9878a80ddcb, reversing
changes made to 6fce88c0af6265a4c8bb014decd55084c219fd0d.