[FIX] hw_blackbox_be: python3 support

Was comparing b'0x02' and '0x02'

closes odoo/odoo#39214

X-original-commit: 838cb0e8
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

addons/hw_blackbox_be/controllers/main.py

@@ -139,7 +139,7 @@ class Blackbox(Thread):
                 etx = ser.read(1)
                 bcc = ser.read(1)
 
-                if stx == chr(0x02) and etx == chr(0x03) and bcc and self._lrc(response) == ord(bcc):
+                if stx == chr(0x02).encode() and etx == chr(0x03).encode() and bcc and self._lrc(response.decode()) == ord(bcc):
                     got_response = True
                     ser.write(chr(0x06).encode())
                 else: