#14422 Avoid logging empty error for intentionally skipped GRDECL keywords

Keywords in invalidPropertyDataKeywords() (e.g. ECHO/NOECHO) are skipped without setting an error message, but readProperties() logged the empty string as an error. Only log when there is an actual message.

ApplicationLibCode/FileInterface/RifEclipseInputPropertyLoader.cpp

@@ -114,7 +114,7 @@ std::map<QString, QString> RifEclipseInputPropertyLoader::readProperties( const
         {
             resultNameAndEclipseNameMap[newResultName] = QString::fromStdString( keywordAndValues.keyword );
         }
-        else
+        else if ( !errorText.isEmpty() )
         {
             RiaLogging::error( errorText.toStdString() );
         }