improve error messages about irrecoverably changed UIDVALIDITY

don't print the actual values, which are meaningless technicalities
to the average user, and can be obtained separately for debugging if
really necessary.
also, fix the omission of the affected mailboxes from one of the
messages.

src/sync.c

@@ -1366,10 +1366,8 @@ box_opened2( sync_vars_t *svars, int t )
 		if (svars->uidval[t] != UIDVAL_BAD && svars->uidval[t] != svars->newuidval[t])
 			fails++;
 	if (fails == 2) {
-		error( "Error: channel %s: UIDVALIDITY of both far and near side changed\n"
-		       "(far side got %u, expected %u; near side got %u, expected %u).\n",
-		       svars->chan->name,
-		       svars->newuidval[F], svars->uidval[F], svars->newuidval[N], svars->uidval[N] );
+		error( "Error: channel %s: UIDVALIDITY of both far side %s and near side %s changed.\n",
+		       svars->chan->name, svars->orig_name[F], svars->orig_name[N]);
 	  bail:
 		svars->ret = SYNC_FAIL;
 		sync_bail( svars );
@@ -1617,10 +1615,8 @@ box_loaded( int sts, message_t *msgs, int total_msgs, int recent_msgs, void *aux
 				// A proper fallback would be fetching more headers (which potentially need
 				// normalization) or the message body (which should be truncated for sanity)
 				// and comparing.
-				error( "Error: channel %s, %s box %s: Unable to recover from UIDVALIDITY change\n"
-				       "(got %u, expected %u).\n",
-				       svars->chan->name, str_fn[t], svars->orig_name[t],
-				       svars->newuidval[t], svars->uidval[t] );
+				error( "Error: channel %s, %s box %s: Unable to recover from UIDVALIDITY change.\n",
+				       svars->chan->name, str_fn[t], svars->orig_name[t] );
 				goto uvchg;
 			}
 			notice( "Notice: channel %s, %s box %s: Recovered from change of UIDVALIDITY.\n",