Tweaks to r41902 "(bug 14634) Show range blocks for IPs"

Tweaks to r41902 "(bug 14634) Show range blocks for IPs"
* Remove the "scan range blocks" checkbox -- doing the range check is sane default behavior, and should Just Work. :)
* Paranoia SQL escaping. We may "know" that the strings will never include something escapable, but then again someone might make a mistake one day. By ensuring we escape them, we have one less thing to worry about, and one less thing to double-check every time we look at this code.

Note that a search for a particular range block currently does not turn up larger range blocks that include it, which it probably should.