remove two lines to prevent crash during compile for the mbed frdm k64f

Dependencies:   Socket lwip-eth lwip-sys lwip

Fork of EthernetInterface by mbed official

Revision:
56:16def471e387
Parent:
55:84000bbe55af
--- a/lwip-eth.lib	Fri Apr 14 13:42:13 2017 +0000
+++ b/lwip-eth.lib	Fri Apr 14 13:43:44 2017 +0000
@@ -1,1 +1,1 @@
-http://mbed.org/users/mbed_official/code/lwip-eth/#6987f08bc079
+https://developer.mbed.org/users/Frostworks/code/lwip-eth/#6987f08bc079