[IMP] hw_scale: fix to avoid conflicts with other driver

There are two scales that are supported, but the Adam scale
possibly won't return any answer so there is no way to detect then
if it is an Adam scale or something else.  As we have not implemented
a detection method for the caliper driver yet, we exclude it from
the devices the scale can detect.  (by comparing /dev/serial/by-id
and by-path)

addons/hw_scale/controllers/main.py

@@ -125,6 +125,7 @@ class Scale(Thread):
         self.scalelock = Lock()
         self.status = {'status':'connecting', 'messages':[]}
         self.input_dir = '/dev/serial/by-path/'
+        self.forbidden_dir = '/dev/serial/by-id/'
         self.weight = 0
         self.weight_info = 'ok'
         self.device = None
@@ -212,15 +213,16 @@ class Scale(Thread):
                     self.set_status('disconnected', 'No RS-232 device found')
                     return None
 
-                devices = [device for device in listdir(self.input_dir)]
-
+                forbidden_devices = [os.readlink(self.forbidden_dir + d) for d in listdir(self.forbidden_dir) if 'usb-Sylvac_Power_USB_A32DV5VM' in d] # Skip special usb link with Sylvac
+                devices = [device for device in listdir(self.input_dir) if os.readlink(self.input_dir + device) not in forbidden_devices]
                 for device in devices:
+                    path = self.input_dir + device
                     driver = hw_proxy.rs232_devices.get(device)
                     if driver and driver != DRIVER_NAME:
                         # belongs to another driver
                         _logger.info('Ignoring %s, belongs to %s', device, driver)
                         continue
-                    path = self.input_dir + device
+
                     for protocol in SCALE_PROTOCOLS:
                         _logger.info('Probing %s with protocol %s', path, protocol)
                         connection = serial.Serial(path,