This change toggles the default behavior of composer and will always store drafts encrypted - but only if user has enabled encryption in the composer. If the "Encrypt" action is not enabled, the draft will not be stored encrypted.
This change also renames the option NeverEncryptDrafts to AlwaysEncryptDrafts to avoid the "double negative" when doing !cfg->neverEncryptDrafts. It's also a neat hack to get the same defaults for all users :-)