oc: cached usercontext updates indexing_context

Instead of use always the one given on initialization

OpenChange/MAPIStoreUserContext.m

@@ -65,7 +65,14 @@ static NSMapTable *contextsTable = nil;
   id userContext;
 
   userContext = [contextsTable objectForKey: username];
-  if (!userContext)
+  if (userContext)
+    {
+      // The indexing_context used when this user context was created
+      // could had been freed, so we have to update it and use the one
+      // that we receive as parameter (which is a valid one for sure).
+      [userContext updateIndexing: indexing];
+    }
+  else
     {
       userContext = [[self alloc] initWithUsername: username
                                     andTDBIndexing: indexing];
@@ -76,6 +83,11 @@ static NSMapTable *contextsTable = nil;
   return userContext;
 }
 
+- (void) updateIndexing: (struct indexing_context *) indexing
+{
+    [mapping updateIndexing: indexing];
+}
+
 - (id) init
 {
   if ((self = [super init]))