[pfcwd] Use floor division in Python3 (sonic-net#1277)

Fix the float division due to recent transfer to Python3, use floor division instead to generate integer result in the PFCWD detect/restore time calculation.

Signed-off-by: Longxiang Lyu <[email protected]>

Author: lolyu

pfcwd/main.py

@@ -359,7 +359,7 @@ def start_default(self):
         port_num = len(list(self.config_db.get_table('PORT').keys()))
 
         # Paramter values positively correlate to the number of ports.
-        multiply = max(1, (port_num-1)/DEFAULT_PORT_NUM+1)
+        multiply = max(1, (port_num-1)//DEFAULT_PORT_NUM+1)
         pfcwd_info = {
             'detection_time': DEFAULT_DETECTION_TIME * multiply,
             'restoration_time': DEFAULT_RESTORATION_TIME * multiply,