handle debug flag consistently

use the environment variable for everything.

gets rid of nagging message to make sure DEBUG isn't enabled in production (was
never a concern anyway due to details of mod_wsgi).
add config helper to register handlers for a logger
remove unused store.py logger
added securerop.log for both interfaces to ossec config
added w permissions for securedrop.log in apparmor profile
added logging config to source and document config.py used in production install
Merge pull request #1 from dolanjs/os-apparmor-ossec

OSSEC apparmor and install scripts fixes for logging change
Merge pull request #310 from garrettr/logging-hotfix

Logging hotfix. Fixes #261.