Bug 906462 - Remove noise backgrounds for about:newtab and about:home; r=dao a=akeybl

--HG--
rename : browser/themes/linux/newtab/noise.png => browser/themes/linux/devtools/noise.png
rename : browser/themes/osx/newtab/noise.png => browser/themes/osx/devtools/noise.png
rename : browser/themes/windows/newtab/noise.png => browser/themes/windows/devtools/noise.png