Revert "Revert "update grenade branches""

We are not gating on n-cpu-partial so it's safe to propose
icehouse -> master grenade upgrades.

This reverts commit 633b702cd9ac62d9fba15f60c20423844b4949b5.

Change-Id: If6f18f86f0f5a2dccd02fb82452c8651436cc5d2
Merge "Revert "Revert "update grenade branches"""