klippy: Report the first error generated

Only update the status message with the first error report.
Subsequent errors are often the result of the first error and
reporting the last error can be misleading.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/klippy.py

@@ -65,6 +65,7 @@ class Printer:
     def get_state_message(self):
         return self.state_message
     def _set_state(self, msg):
+        if self.state_message in (message_ready, message_startup):
             self.state_message = msg
         if (msg != message_ready
             and self.start_args.get('debuginput') is not None):