MainBuffer::putData() : remove constant (=100) volume argument

sflphone-common/src/audio/alsa/alsalayer.cpp

sflphone-common/src/audio/audiolayer.cpp

sflphone-common/src/audio/audiortp/AudioRtpRecordHandler.cpp

sflphone-common/src/audio/mainbuffer.cpp

sflphone-common/src/audio/mainbuffer.h

sflphone-common/src/audio/pulseaudio/pulselayer.cpp

sflphone-common/src/iax/iaxvoiplink.cpp

sflphone-common/test/mainbuffertest.cpp