Update the authority signing key blacklist

Now it only has dannenberg
Merge remote-tracking branch 'origin/maint-0.2.3' into maint-0.2.4
remove note about dannenberg; it has upgraded.
Merge remote-tracking branch 'origin/maint-0.2.3' into maint-0.2.4
Merge remote-tracking branch 'origin/maint-0.2.4'