trace-cmd: Have msg_handle part of the buffer instance

To allow for recording of the host as well as for the network, we need to
have the msg_handle associated to the buffer instance and not global. This
also will allow for recording buffer instances to network and host, as well
as sending data to multiple hosts.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2 files changed