Fix H307 violations and re-enable gating

H307 is a new rule in hacking 0.9, so fix new violations and
re-enable gating.

Change-Id: I805d10427ebeaee36589936f77a2cf0932c1378e
Remove useless sources.json

Change-Id: If0595a079e5cb153c18e05cbd3ddaa64760638f1
update default_log_levels set by ceilometer

the current log levels are pretty old. update the current list to
extend current default default_log_level defined in oslo-incubator
and adding in stevedore and keystoneclient levels

Change-Id: I239645ef641613a994a48f20c0238e76dc9660f2
Partial-Bug: #1294789
Merge "Fix H307 violations and re-enable gating"
Merge "update default_log_levels set by ceilometer"
Merge "Remove useless sources.json"