oc-mail: Remove unnecessary time shift in date for new mails

The MIME type can store the date in UTC and the clients are
responsible on showing correctly to the client as it does.

OpenChange/MAPIStoreMailVolatileMessage.m

@@ -29,7 +29,6 @@
 #import <Foundation/NSData.h>
 #import <Foundation/NSDictionary.h>
 #import <Foundation/NSString.h>
-#import <Foundation/NSTimeZone.h>
 #import <Foundation/NSValue.h>
 #import <NGExtensions/NGHashMap.h>
 #import <NGExtensions/NSObject+Logs.h>
@@ -673,8 +672,6 @@ FillMessageHeadersFromProperties (NGMutableHashMap *headers,
   date = [mailProperties objectForKey: MAPIPropertyKey (PR_CLIENT_SUBMIT_TIME)];
   if (date)
     {
-      date = [date addYear: 0 month: 0 day: 0
-                      hour: 0 minute: 0 second: [[date timeZone] secondsFromGMT]];
       [headers addObject: [date rfc822DateString] forKey: @"date"];
     }
   [headers addObject: @"1.0" forKey: @"MIME-Version"];