Update ipinfo.py

I've tested with  Nexus5548-6.0(2)N2(4) this code. 
When a user enters a IP, you can check the MAC / VLAN / Interface / Description information.

Example Result)
F_DMZ_NEXUS_A_1# python ipinfo.py 10.10.10.11
 202.3.31.251 : Not found IP Address Infomation
4F_DMZ_NEXUS_A_1# python ipinfo.py 10.10.10.11
================================================
      IP Info : NetworkZIGI   2014.07.19        
================================================
IP-Address      : 10.10.10.11
Mac-Address     : 0012.3456.789A
Vlan            : 20
Interface       : E12/3
Description     : NetworkZIGI Blog Web Server