tools lib traceevent: Introduce pevent_errno

tools lib traceevent: Introduce pevent_errno

Define and use error numbers for pevent_parse_event() and get rid of
die() and do_warning() calls. If the function returns non-zero value,
the caller can check the return code and do appropriate things.

I chose the error numbers to be negative not to clash with standard
errno, and as usual, 0 for success.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1345618831-9148-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>