Add IDB_COMPANION_LOCAL env var
Add IDB_COMPANION_LOCAL env var

Summary: Sometimes easier to inject env than interpolate args

Reviewed By: yancouto

Differential Revision: D21449578

fbshipit-source-id: e9175181b4a067e602207e618a13c98af7eaf5a6

facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl