oc-mail: Check the number of uids fetched on synchroniseCache

Equals to the number of uids requested.

There are corner-cases when this is not happening, we don't know yet
why this is happening but IMAP server log should do the trick.

This avoids to launch a NSException trying to access an element
outside the array bounds.

OpenChange/MAPIStoreMailFolder.m

@@ -599,7 +599,7 @@ _compareFetchResultsByMODSEQ (id entry1, id entry2, void *data)
   uint64_t lastModseqNbr;
   EOQualifier *searchQualifier;
   NSArray *uids, *changeNumbers;
-  NSUInteger count, max;
+  NSUInteger count, max, nFetched;
   NSArray *fetchResults;
   NSDictionary *result;
   NSData *changeKey;
@@ -678,6 +678,13 @@ _compareFetchResultsByMODSEQ (id entry1, id entry2, void *data)
         = [fetchResults sortedArrayUsingFunction: _compareFetchResultsByMODSEQ
                                          context: NULL];
 
+      nFetched = [fetchResults count];
+      if (nFetched != max) {
+        [self errorWithFormat: @"Error fetching UIDs. Asked: %d Received: %d."
+              @"Check the IMAP conversation for details", max, nFetched];
+        return NO;
+      }
+
       for (count = 0; count < max; count++)
         {
           result = [fetchResults objectAtIndex: count];