[sfputilbase] Fix xcvr and sfpshow crash with OSFP (sonic-net#63)

* fix xcvr crash when read OSFP DOM threshold
* fix sfpshow crash when trying to decodes OSFP's specification_compliance

sonic_platform_base/sonic_sfp/sfputilbase.py

@@ -777,7 +777,7 @@ def get_transceiver_info_dict(self, port_num):
  transceiver_info_dict['ext_rateselect_compliance'] = 'N/A'
  transceiver_info_dict['cable_type'] = 'N/A'
  transceiver_info_dict['cable_length'] = 'N/A'
- transceiver_info_dict['specification_compliance'] = 'N/A'
+ transceiver_info_dict['specification_compliance'] = '{}'
  transceiver_info_dict['nominal_bit_rate'] = 'N/A'
 
  else:
@@ -1103,7 +1103,11 @@ def get_transceiver_dom_threshold_info_dict(self, port_num):
  ]
  transceiver_dom_threshold_info_dict = dict.fromkeys(dom_info_dict_keys, 'N/A')
 
- if port_num in self.qsfp_ports:
+ if port_num in self.osfp_ports:
+ # Below part is added to avoid fail xcvrd, shall be implemented later
+ return transceiver_dom_threshold_info_dict
+
+ elif port_num in self.qsfp_ports:
  file_path = self._get_port_eeprom_path(port_num, self.IDENTITY_EEPROM_ADDR)
  if not self._sfp_eeprom_present(file_path, 0):
  return None