Add a flag to pevent that will let the callers be able to set it and
keep the system, and perhaps even normal plugins from being loaded.

This is useful when plugins might hide certain information and seeing
the raw events shows what may be going on.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20140603032223.678098063@goodmis.orgSigned-off-by: Jiri Olsa <jolsa@kernel.org>