avoid warning due to unclosed resource in SensorDataImportServlet

Change-Id: I4a5a5efdc703cbb0b727335be0ec73b5103c6ddc

java/com.sap.sailing.server.gateway/src/com/sap/sailing/server/gateway/trackfiles/impl/SensorDataImportServlet.java

@@ -77,6 +77,7 @@ public class SensorDataImportServlet extends AbstractFileUploadServlet {
                 }
             }
             if (importerToUse == null) {
+                in.close();
                 throw new RuntimeException("Sensor importer not found");
             }
             in.mark(READ_BUFFER_SIZE);