Use md5sum so that it takes less time of checking
trace logs update. Since busybox tail/cat takes too
long time to read the trace log, this uses md5sum
to check whether trace log is updated or not.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>