Move ga.js to bottom of the head to
Move ga.js to bottom of the head to

to verify with Webmaster Tools it's recommended to move ga.js to the
bottom of the <head>. This is non-blocking script, so we should be okay
in term of performance.

mozilla/donate.mozilla.org,jbuck/donate.mozilla.org,alicoding/donate.mozilla.org,ScottDowne/donate.mozilla.org