-Werror,-Wunused-variable

Unused ever since it got introduced in 62b337a3d6
"Unit test for removeTextContext."

(Found with an experimental Clang build supporting __attribute__((warn_unused))
on individual ctors rather than just whole class types, and the corresponding
css::uno::Reference ctor marked accordingly.)

Change-Id: Id80b031625134ea6b4d679bfb774fc253206ae18
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/150374
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

desktop/qa/desktop_lib/test_desktop_lib.cxx

@@ -2062,7 +2062,6 @@ void DesktopLOKTest::testInput()
 {
     // Load a Writer document, enable change recording and press a key.
     LibLODocument_Impl* pDocument = loadDoc("blank_text.odt");
-    uno::Reference<beans::XPropertySet> xPropertySet(mxComponent, uno::UNO_QUERY);
 
     Scheduler::ProcessEventsToIdle(); // Get focus & other bits setup.