SfxDocumentMetaData: suppress some spurious warnings

These always trigger on a new document.

Change-Id: Ied60f52c4dc348b2b18f6dc8c30204ee3dc56f29

sfx2/source/doc/SfxDocumentMetaData.cxx

@@ -525,7 +525,7 @@ textToDateOrDateTime(css::util::Date & io_rd, css::util::DateTime & io_rdt,
                 &io_rd, io_rdt, o_rIsDateTime, &o_rTimeZone, i_text)) {
         return true;
     } else {
-        SAL_WARN("sfx.doc", "Invalid date: " << i_text );
+        SAL_WARN_IF(!i_text.isEmpty(), "sfx.doc", "Invalid date: " << i_text);
         return false;
     }
 }
@@ -537,7 +537,7 @@ textToDateTime(css::util::DateTime & io_rdt, const OUString& i_text) throw ()
     if (::sax::Converter::parseDateTime(io_rdt, 0, i_text)) {
         return true;
     } else {
-        SAL_INFO("sfx.doc", "Invalid date: " << i_text);
+        SAL_WARN_IF(!i_text.isEmpty(), "sfx.doc", "Invalid date: " << i_text);
         return false;
     }
 }
@@ -589,7 +589,7 @@ throw ()
     if (::sax::Converter::convertDuration(io_rDur, i_rText)) {
         return true;
     } else {
-        SAL_WARN("sfx.doc", "Invalid duration: " << i_rText );
+        SAL_WARN_IF(!i_rText.isEmpty(), "sfx.doc", "Invalid duration: " << i_rText);
         return false;
     }
 }