Added an administration setting to allow issue start date to be defaulted to blank (nil) at issue creation (#2269).

Based on the patch of #2277 contributed by Mischa The Evil.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@7733 e93f8b46-1217-0410-a6f0-8f06a7374b81

config/settings.yml

@@ -123,6 +123,8 @@ cross_project_issue_relations:
   default: 0
 issue_group_assignment:
   default: 0
+default_issue_start_date_to_creation_date:
+  default: 1
 notified_events:
   serialized: true
   default: