perf scripts python: exported-sql-viewer.py: Use argparse module for argument parsing

from __future__ import print_function

import sys

import argparse

import weakref

import threading

import string

# Main

def Main():

	if (len(sys.argv) < 2):

		printerr("Usage is: exported-sql-viewer.py {<database name> | --help-only}");

		raise Exception("Too few arguments")

	dbname = sys.argv[1]

	if dbname == "--help-only":

	usage_str =	"exported-sql-viewer.py [--pyside-version-1] <database name>\n" \

			"   or: exported-sql-viewer.py --help-only"

	ap = argparse.ArgumentParser(usage = usage_str, add_help = False)

	ap.add_argument("dbname", nargs="?")

	ap.add_argument("--help-only", action='store_true')

	args = ap.parse_args()

	if args.help_only:

		app = QApplication(sys.argv)

		mainwindow = HelpOnlyWindow()

		mainwindow.show()

		err = app.exec_()

		sys.exit(err)

	dbname = args.dbname

	if dbname is None:

		ap.print_usage()

		print("Too few arguments")

		sys.exit(1)

	is_sqlite3 = False

	try:

		f = open(dbname, "rb")