Auto merge of #237 - changlan:patch-1, r=mrmonday
Auto merge of #237 - changlan:patch-1, r=mrmonday

Fix a typo in arp.rs

mrmonday/libpnet,libpnet/libpnet,libpnet/libpnet,mrmonday/libpnet,mrmonday/libpnet,mrmonday/libpnet,libpnet/libpnet,libpnet/libpnet