Revert "update grenade branches"

This reverts commit 1ab574df7c6b97dcc32f9b9191ff6bb5ac61e4e0.

Grenade does not know how to upgrade from icehouse yet. This change
can only go in once grenade is aware of how to set up an "old" icehouse
install.

Partial-Bug: #1309324
Change-Id: I806850410a31e40aea81f3a57b48f3d98bef9dd2