[queuestat CLI] Enable queuestat to get counters with missing data

If self.db.get returns an empty string due to missing fields in
countersDB, queuestat will crash instead of setting STATUS_NA.

Fixed this problem by checking if counter_data == ''

Signed-off-by: Roy Yi <[email protected]>

Author: royyi8

scripts/queuestat

@@ -182,7 +182,7 @@ class Queuestat(object):
             for counter_name, pos in counter_bucket_dict.items():
                 full_table_id = COUNTER_TABLE_PREFIX + table_id
                 counter_data =  self.db.get(self.db.COUNTERS_DB, full_table_id, counter_name)
-                if counter_data is None:
+                if counter_data is None or counter_data == ''::
                     fields[pos] = STATUS_NA
                 elif fields[pos] != STATUS_NA:
                     fields[pos] = str(int(counter_data))