How to deactivate Siri on Home Button

Hi guys,

my iphone 6 has the newest ios version (8.2). There seems to be a bug regarding siri. I can not disable siri in any way! I tried the solution from this post: How to disable voice control (ios 8) but it did not work. Disabling siri seems not to have any effect at all.

This really p.i.s.s.e.s me off! In every meeting its the same s.h.i.t. I have the phone in my pocket and by accident the home button presses against the chair and voila, siri. SIRI! Argh! No really, this is just so annoying! How the f* can i disable this once and for all!