bluetooth: correct rfcomm command and reply formatting
requested to merge igor.v.kovalenko/pulseaudio:pr/fix-rfcomm-write-command-line-format-in-master into master
The format of COMMAND line sent from HS to AG is COMMAND<cr>
The format of RESPONSE line sent from AG to HS is <cr><lf>RESPONSE<cr><lf>
Split rfcomm_write into rfcomm_write_command and rfcomm_write_response to handle line formatting correctly.