fix: ccnpack config on central node enum

* For lab test, where number of interface is one

FofbTool/Configuration.py

@@ -261,7 +261,7 @@ def centralnode_configure_ccn(nbpm=None, npsc=None):
         npsc = getconf("npsc", "ccn", 'centralnode', 'i')
     logger.debug("{} psc allowed in the ethernet frame on {}".format(nbpm, p))
 
-    for n in range(4):
+    for n in range(len(nbpm)):
         maclen = npsc*6+10
         logger.debug("Configure packeter {} framesize (mac length) to {}".format(n, maclen))
         prx["ccnpack{}_framesize".format(n)] = maclen