fix race condition in service list compares

there is a small chance that between the 2 service queries that
the service list is updated by the periodic job. We'll assume
stability of the service host list in the regular case, but
the other metadata is changeable, so only compary the binary
lists.

Fixes bug #1205450

Change-Id: I29f687d4279b79f192de3bae3d15abebd3d858a1
Merge "fix race condition in service list compares"