We want to force users to enter ip addresses for both graphite_host
and grafana_host, but using "and" catches scenarios when both
variables were missing. Changing this conditional to "or" will
catch scenarios where one or the other might be missing too.
Patchset #1: change "and" to "or"
Patchset #2: minor commit description correction
Patchset #3: wrap commit comments cleaner
Change-Id: Ic0553a398c491ba414b194b8a330ea2b04a6eb44
abc123dc6d