Fix text metrics calculation in Xft support for lwlib

* lwlib/lwlib-Xaw.c (get_text_width_and_height) [HAVE_XFT]:
* lwlib/xlwmenu.c (string_width) [HAVE_XFT]: Use xOff member instead of width.
1 job for master in 52 minutes and 2 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #1455
test-all

00:52:02