Use the correct way to format default in optparse
@@ -124,7 +124,7 @@ class InstallCommand(RequirementCommand):
default='only-if-needed',
choices=['only-if-needed', 'eager'],
help='Determines how dependency upgrading should be handled '
- '(default: %(default)s). '
+ '[default: %default]. '
'"eager" - dependencies are upgraded regardless of '
'whether the currently installed version satisfies the '
'requirements of the upgraded package(s). '
