xcvrd: fix test issue and address more comments

Author: Staphylo

sonic-xcvrd/xcvrd/dom/dom_mgr.py

@@ -120,7 +120,7 @@ def run(self):
             self.task_worker()
         except Exception as e:
             self.log_error("Exception occurred at {} thread due to {}".format(threading.current_thread().getName(), repr(e)))
-            xcvrd.log_exception_traceback()
+            common.log_exception_traceback()
             self.exc = e
             self.main_thread_stop_event.set()
 

sonic-xcvrd/xcvrd/xcvrd_utilities/xcvr_table_helper.py

@@ -55,7 +55,7 @@
 class XcvrTableHelper:
     def __init__(self, namespaces):
         self.int_tbl, self.dom_tbl, self.dom_threshold_tbl, self.status_tbl, self.app_port_tbl, \
-               self.cfg_port_tbl, self.state_port_tbl, self.pm_tbl, self.firmware_info_tbl = {}, {}, {}, {}, {}, {}, {}, {}, {}
+		self.cfg_port_tbl, self.state_port_tbl, self.pm_tbl, self.firmware_info_tbl = {}, {}, {}, {}, {}, {}, {}, {}, {}
         self.state_db = {}
         self.appl_db = {}
         self.cfg_db = {}