Fix all "dangerous-default-value" pylint warnings.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/command.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/command.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/command.py b/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/command.py
index 5a2896b480b334f0ceed4d06fbd653df4e7e6139..dcd202bb9fbf1a5aa62801846e1102b71181849b 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/command.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/command.py
@@ -121,8 +121,8 @@ class Command(object):
 
     # main() exists so that Commands can be turned into stand-alone scripts.
     # Other parts of the code will likely require modification to work stand-alone.
-    def main(self, args=sys.argv):
-        (options, args) = self.parse_args(args)
+    def main(self, args=None):
+        options, args = self.parse_args(args)
         # Some commands might require a dummy tool
         return self.check_arguments_and_execute(options, args)