Remove deprecated and unused run_and_throw_if_fail from webkitpy

Tools/Scripts/webkitpy/common/checkout/scm/scm_unittest.py

 # Copyright (C) 2009 Google Inc. All rights reserved.
 # Copyright (C) 2009 Apple Inc. All rights reserved.
 # Copyright (C) 2011 Daniel Bates (dbates@intudata.com). All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #    * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
@@ skipping 76 matching lines @@
     def _remove(self, path):
         self.fs.remove(path)
 
     def _rmtree(self, path):
         self.fs.rmtree(path)
 
     def _run(self, *args, **kwargs):
         return self.executive.run_command(*args, **kwargs)
 
     def _run_silent(self, args, **kwargs):
-        self.executive.run_and_throw_if_fail(args, quiet=True, **kwargs)
+        self.executive.run_command(args, **kwargs)
 
     def _write_text_file(self, path, contents):
         self.fs.write_text_file(path, contents)
 
     def _write_binary_file(self, path, contents):
         self.fs.write_binary_file(path, contents)
 
     def _make_diff(self, command, *args):
         # We use this wrapper to disable output decoding. diffs should be treated as
         # binary files since they may include text files of multiple differnet encodings.
@@ skipping 588 matching lines @@
         scm = self.make_scm()
         scm.find_checkout_root = lambda path: ''
         scm._run_git = lambda args: 'Date: 2013-02-08 08:05:49 +0000'
         self.assertEqual(scm.timestamp_of_revision('some-path', '12345'), '2013-02-08T08:05:49Z')
 
         scm._run_git = lambda args: 'Date: 2013-02-08 01:02:03 +0130'
         self.assertEqual(scm.timestamp_of_revision('some-path', '12345'), '2013-02-07T23:32:03Z')
 
         scm._run_git = lambda args: 'Date: 2013-02-08 01:55:21 -0800'
         self.assertEqual(scm.timestamp_of_revision('some-path', '12345'), '2013-02-08T09:55:21Z')