Revert "fdo#43869 use the old rtf importer for paste"

This reverts commit bb147bbb801b53dba8928340df7e2aa2d4545349. It's no
longer needed, now the new importer supports importing to an existing
document.
diff --git a/sw/source/filter/rtf/swparrtf.cxx b/sw/source/filter/rtf/swparrtf.cxx
index 8f5a554..13216ca 100644
--- a/sw/source/filter/rtf/swparrtf.cxx
+++ b/sw/source/filter/rtf/swparrtf.cxx
@@ -26,7 +26,6 @@
#include <tools/helpers.hxx>
#include <svl/itemiter.hxx>
#include <svtools/rtftoken.h>
#include <svtools/miscopt.hxx>
#include <svl/intitem.hxx>
#include <editeng/fhgtitem.hxx>
#include <editeng/ulspitem.hxx>
@@ -223,11 +222,6 @@

extern "C" SAL_DLLPUBLIC_EXPORT Reader* SAL_CALL ImportRTF()
{
    // Use the old rtf importer by default for paste, till the new one supports
    // undo stack and PaM.
    SvtMiscOptions aMiscOptions;
    if (!aMiscOptions.IsExperimentalMode())
        return new RtfReader();
    return new SwRTFReader();
}