Fix: do not print strackstrace on stdout, use logger

src/main/java/com/sheepit/client/hardware/hwid/HWIdentifier.java

@@ -39,7 +39,6 @@ public class HWIdentifier {
 			return hwid;
 		}
 		catch (Exception e) {
-			e.printStackTrace();
 			log.error("HWIdentifier::getHardwareHash could not retrieve hash: " + e);
 			return "unknown";
 		}