DO NOT MERGE Fix potential DoS caused by delivering signal to BT process

Bug: 28885210
Change-Id: I63866d894bfca47464d6e42e3fb0357c4f94d360

 Conflicts:
	btif/co/bta_hh_co.c
	btif/src/btif_core.c
Merge conflict resolution of ag/1161415 (referencing ag/1164670)
- Directly into mnc-mr2-release

void btsnoop_net_close() {
#if (!defined(BT_NET_DEBUG) || (BT_NET_DEBUG != TRUE))
 return; // Disable using network sockets for security reasons
#endif

 if (listen_thread_valid_) {
    shutdown(listen_socket_, SHUT_RDWR);
    pthread_join(listen_thread_, NULL);
    safe_close_(&client_socket_);
    listen_thread_valid_ = false;
 }
}

void btsnoop_net_close() {
#if (!defined(BT_NET_DEBUG) || (BT_NET_DEBUG != TRUE))
 return; // Disable using network sockets for security reasons
#endif

 if (listen_thread_valid_) {
    shutdown(listen_socket_, SHUT_RDWR);
    pthread_join(listen_thread_, NULL);
    safe_close_(&client_socket_);
    listen_thread_valid_ = false;
 }
}
