Disable buchets detection code, as we are not using it for now (bug 1003266)

https://bugzilla.mozilla.org/show_bug.cgi?id=1003266
I'll add precise timings later (see my comment below for measurements I did earlier, but I didn't keep the raw data so I'll redo the tests) but it's both reasons at the same time. 

For the slowness part... on tarako, we gained **seconds** of loading time when we completely removed buchets (https://bugzilla.mozilla.org/show_bug.cgi?id=1003186). 

Since we can't use it in its present state anyway, and it's super slow on some devices, it doesn't make sense to keep it for the moment.