[libvirt] [PATCH] Sanitize qemu monitor reads

Reading from the qemu monitor pulls in a whole bunch of useless control characters. For example, sending the command 'somecomm' to the monitor returns: somecomm unknown command: 'somecomm' (qemu) Which is 36 characters, however we end up reading over 200. The amount we read actually grows quadratically as a function of the command length. This prevents us from reporting monitor output to the user (incase some command fails) and seriously diminishes the value of the domain logfiles. The attached patch tries to sanitize this a bit. After reading all the output, we search for the first occurrence of the full command string. If found, we search from there for the first newline (which marks the beginning of the monitor response). If these are found, we only return the command, and everything after the newline. If only the command is found, we just drop everything before it. I've tested this on f9 and f8, there didn't seem to be any problems. I think this should be pretty future proof as well, so we hopefully won't be throwing out anything valuable. Thanks, Cole