Improving comment in monitors.py
Improving comment in monitors.py

This patch will improve the comment below abstract method pull_data
which can be defined for pulling data from bay and pod as well but
comment says bay only.

Change-Id: I86cb822dc72bc9805d2c38405012206991110438

openstack/magnum,jay-lau/magnum,openstack/magnum,dimtruck/magnum,dimtruck/magnum,ArchiFleKs/magnum,ArchiFleKs/magnum