Remove duplicate StatTutor requirement
Remove duplicate StatTutor requirement

Things got wonky with the backport of master into the Ficus merge branch.

Stanford-Online/edx-platform,caesar2164/edx-platform,Stanford-Online/edx-platform,Stanford-Online/edx-platform,caesar2164/edx-platform,caesar2164/edx-platform,caesar2164/edx-platform,Stanford-Online/edx-platform