Already existing snoop file is renamed by adding ".old" suffix before
new one is created. This is useful in case phone is restarted so logs
are not overwritten and for this reason it's only applied in case
default snoop file name is used.
This tool is intended to be run as Android service. It supports
writing HCI snoop data in old btsnoop format only. By default traffic
is stored in /sdcard/btsnoop_hci.log file (can be overridded with
option - mainly for testing on Linux host). Only index 0 is sniffed.