Disable opening network debug ports for security reasons

Disable opening network debug ports for security reasons

By default, we open up to three TCP ports that are used
for debugging purpose:

 * TCP port 8872 - used for forwarding btsnoop logs at real time
   Note: the port is open only if "Bluetooth HCI snoop log" is enabled
   in the Developer options
 * TCP port 8873 - used for HCI debugging
 * TCP port 8879 - used for debugging the Bluetooth counters

Those ports are disabled by default.
To enable, the following #define should be added at the top of the
corresponding file(s): btcore/src/counter.c hci/src/btsnoop_net.c
hci/src/hci_inject.c

   #define BT_NET_DEBUG TRUE

Bug: 24371736

Change-Id: I5cb43af1a5d29c331eb5ef61a24dccbe95df6f40