revert: feat add url for creating account on login page

SoObjects/SOGo/SOGoSystemDefaults.h

@@ -157,9 +157,6 @@ NSComparisonResult languageSort(id el1, id el2, void *context);
 
 - (BOOL)isURLEncryptionEnabled;
 - (NSString *)urlEncryptionPassphrase;
-
-- (NSString *)urlCreateAccount;
-
 - (BOOL)enableMailCleaning;
 
 @end

SoObjects/SOGo/SOGoSystemDefaults.m

@@ -1157,11 +1157,6 @@ NSComparisonResult languageSort(id el1, id el2, void *context)
   return disableExport;
 }
 
-- (NSString *)urlCreateAccount
-{
-  return [self stringForKey: @"SOGoURLCreateAccount"];
-}
-
 - (BOOL) enableMailCleaning
 {
   return [self boolForKey: @"SOGoEnableMailCleaning"];