Fix nokogiri typo

[todb-r7]

There is no 'Nokogiri,' only 'nokogiri'

[SeeRM #8730]

[todb-r7]

And yes, it's a single-bit change.

I take it @wchen-r7's dev environment is case-insensitive.

[wchen-r7]

I guess.

AUS-MAC-1039:tiff wchen$ irb
1.9.3-p392 :001 > require 'Nokogiri'
 => true 
1.9.3-p392 :002 > exit
AUS-MAC-1039:tiff wchen$ irb
1.9.3-p392 :001 > require 'nokogiri'
 => true 
1.9.3-p392 :002 >