Remove use of GRENADE_PHASE

Recently, devstack-gate accidentally stopped setting these values and
there appeared to be no fallout.  Looking closer, they appear to be
no longer used by Grenade.  This removes them from sample localrcs
and docs.

Change-Id: I4d1ec41bac5a05241069963d1bcd2df4070f5ea2
Merge "Remove use of GRENADE_PHASE"