This is a slightly modified version of the connect_throttle from znc-extra.
If a login attempt fails, all further login attempts from that source IP are
blocked for some time (by default one minute).
git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1390 726aef4b-f618-498e-8847-2d620e286838
