Removed convertNeutronIDToKey(String) calls.

The convertNeutronIDToKey(String) method of BaseHandler class converts
Neutron ID.
Because PortHandler class just uses Neutron ID for log output, it does
not need to use convertNeutronIDToKey(String).

Change-Id: I025b1db5cdc0c635a75a286f6eeb961c5233f7fa
Signed-off-by: Hideyuki Tai <h-tai@cd.jp.nec.com>