trace: tighten up trace-events regex to fix bad parse

trace: tighten up trace-events regex to fix bad parse

Use \w for properties and trace event names since they are both drawn
from [a-zA-Z0-9_] character sets.

The .* for matching properties was too aggressive and caused the
following failure with foo(int rc) "(this is a test)":

  Traceback (most recent call last):
    File "scripts/tracetool.py", line 139, in <module>
      main(sys.argv)
    File "scripts/tracetool.py", line 134, in main
      binary=binary, probe_prefix=probe_prefix)
    File "scripts/tracetool/__init__.py", line 334, in generate
      events = _read_events(fevents)
    File "scripts/tracetool/__init__.py", line 262, in _read_events
      res.append(Event.build(line))
    File "scripts/tracetool/__init__.py", line 225, in build
      return Event(name, props, fmt, args, arg_fmts)
    File "scripts/tracetool/__init__.py", line 185, in __init__
      % ", ".join(unknown_props))
  ValueError: Unknown properties: foo(int, rc)

Cc: Lluís Vilanova <vilanova@ac.upc.edu>
Reported-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1411468626-20450-1-git-send-email-stefanha@redhat.com