Fix ISSUE #9
Fix ISSUE #9

Deregistration message is now confirmable.
Don't care about the server response.

marcostoc/liblwm2m,javiergp/liblwm2m,sbernard31/liblwm2m,fab13n/liblwm2m,dientaufan/liblwm2m,domedambrosio/liblwm2m,kartben/liblwm2m,Passific/liblwm2m,01org/liblwm2m,1248/liblwm2m