sw: let getProperty fail more helpfully

Change-Id: Ibca942235060c5b3a6215325e262bacbc464f2a4
diff --git a/sw/qa/extras/inc/swmodeltestbase.hxx b/sw/qa/extras/inc/swmodeltestbase.hxx
index c4cbeeb..e2ce0f5 100644
--- a/sw/qa/extras/inc/swmodeltestbase.hxx
+++ b/sw/qa/extras/inc/swmodeltestbase.hxx
@@ -425,7 +425,9 @@ protected:
        T data;
        if (!css::uno::fromAny(properties->getPropertyValue(name), &data))
        {
            CPPUNIT_FAIL("the property is of unexpected type or void");
            OString const msg("the property is of unexpected type or void: "
                    + OUStringToOString(name, RTL_TEXTENCODING_UTF8));
            CPPUNIT_FAIL(msg.getStr());
        }
        return data;
    }
@@ -437,7 +439,9 @@ protected:
        T data = T();
        if (!(properties->getPropertyValue(name) >>= data))
        {
            CPPUNIT_FAIL("the property is of unexpected type or void");
            OString const msg("the property is of unexpected type or void: "
                    + OUStringToOString(name, RTL_TEXTENCODING_UTF8));
            CPPUNIT_FAIL(msg.getStr());
        }
        return data;
    }