Remove SITE_READONLY setting (we'll handle things with read_preferences instead)
Remove some code duplication
Check if we're connected to a primary before trying to write - fail only when necessary (OPS-2592)
Merge pull request #1 from olivierlefloch/olefloch/OPS-2592/still_redirect_if_no_primary

Olefloch/ops 2592/still redirect if no primary