perf trace/scripting: Add support for script args

perf trace/scripting: Add support for script args

One oversight of the original scripting_ops patch was a lack of
support for passing args to handler scripts.  This adds
argc/argv to the start_script() scripting_op, and changes the
rw-by-file script to take 'comm' arg rather than the 'perf'
value currently hard-coded.  It also takes the opportunity to do
some related minor cleanup.

Signed-off-by: Tom Zanussi <[email protected]>
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <1260867220[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>