Remove a bunch of unused webkitpy code from tool/, common/checkout/ and common/config/

Tools/Scripts/webkitpy/tool/commands/stepsequence.py

Index: Tools/Scripts/webkitpy/tool/commands/stepsequence.py
diff --git a/Tools/Scripts/webkitpy/tool/commands/stepsequence.py b/Tools/Scripts/webkitpy/tool/commands/stepsequence.py
index 894771276e16991a5df1cba81a8f15eb985accb0..c48c2c4d49372350f7b8ecd8de4be77ae4b7f56c 100644
--- a/Tools/Scripts/webkitpy/tool/commands/stepsequence.py
+++ b/Tools/Scripts/webkitpy/tool/commands/stepsequence.py
@@ -31,7 +31,6 @@ import sys
 
 from webkitpy.tool import steps
 
-from webkitpy.common.checkout.scm import CheckoutNeedsUpdate
 from webkitpy.common.system.executive import ScriptError
 
 _log = logging.getLogger(__name__)
@@ -79,12 +78,6 @@ class StepSequence(object):
             state = {}
         try:
             self._run(tool, options, state)
-        except CheckoutNeedsUpdate, e:
-            _log.info("Commit failed because the checkout is out of date. Please update and try again.")
-            if options.parent_command:
-                command = tool.command_by_name(options.parent_command)
-                command.handle_checkout_needs_update(tool, state, options, e)
-            self.exit_after_handled_error(e)
         except ScriptError, e:
             if not options.quiet:
                 _log.error(e.message_with_output())