Moving average trendline equation: remove initialisation

Change-Id: I3fa01a2d03e7de6438d0db0685e53e6b7ca6c25a
Reviewed-on: https://gerrit.libreoffice.org/19218Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>

chart2/source/tools/MovingAverageRegressionCurveCalculator.cxx

@@ -103,11 +103,7 @@ OUString MovingAverageRegressionCurveCalculator::ImplGetRepresentation(
     const uno::Reference< util::XNumberFormatter >& /*xNumFormatter*/,
     ::sal_Int32 /*nNumberFormatKey*/ ) const
 {
-    OUStringBuffer aBuf( "f(x) = N/A");
-
-    aBuf = SCH_RESSTR( STR_OBJECT_MOVING_AVERAGE_WITH_PARAMETERS );
-
-    return aBuf.makeStringAndClear();
+    return SCH_RESSTR( STR_OBJECT_MOVING_AVERAGE_WITH_PARAMETERS );
 }
 
 } //  namespace chart