Followup fix for https://rbcommons.com/s/twitter/r/619/
Restore Context after mocking it for tests (fixes CI); fix dep

Testing Done:
./build-support/bin/ci.sh

Reviewed at https://rbcommons.com/s/twitter/r/731/
Fix bad dep.

Testing Done:
CI spinning here: https://travis-ci.org/pantsbuild/pants/builds/30800681

Bugs closed: 392

Reviewed at https://rbcommons.com/s/twitter/r/742/
Merge branch 'master' into lahosken_pagetree
gratuitous change. let's run ci again now that master's green