When deleting a note via /#-<key> or listening the available notes via /#?, the
code somehow managed to add a note.
Also, this fixes checking for empty notes.
Found by tomaw, thanks.
git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1978 726aef4b-f618-498e-8847-2d620e286838