For some reason re-using the DC from SalGraphics results in
GetFontData() returning GDI_ERROR and we fail to read the font’s “cmap”
table. The wired thing is that this happens only for fonts that were
not used before, so if you open a document directly the fallback works
but if you open start center or blank Writer document you get no
fallback. GDI is “interesting”.

Change-Id: Ic23095cabbd2623717271ce5d89bea75dca76a9a