Bright:Change the external network domain

• useful for any time the local uni network changes or if there's a mistake in the original domain name
• In this instance, montana was spelt wrong below:

[root@hyalite ~]# cmsh 
[hyalite]% network list 
Name (key)         Type         Netmask bits   Base address     Domain name          IPv6
------------------ ------------ -------------- ---------------- -------------------- ----
externalnet        External     29             153.90.1.8       montanna.edu         no  
globalnet          Global       0              0.0.0.0          cm.cluster           no  
highspeed          Internal     24             172.23.19.0      eth.cluster          no  
mgmt               Internal     24             172.23.17.0      ipmi.cluster         no  
[hyalite]% network 

[hyalite->network]% set externalnet domainname montana.edu
[hyalite->network*]% list
Name (key)         Type         Netmask bits   Base address     Domain name          IPv6
------------------ ------------ -------------- ---------------- -------------------- ----
externalnet        External     29             153.90.1.8       montana.edu          no  
globalnet          Global       0              0.0.0.0          cm.cluster           no  
highspeed          Internal     24             172.23.19.0      eth.cluster          no  
mgmt               Internal     24             172.23.17.0      ipmi.cluster         no  
[hyalite->network*]% commit
Successfully committed 1 Networks
[hyalite->network]% 
Tue Jan  6 15:06:46 2015 [notice] hyalite: Service dhcpd was restarted
[hyalite->network]% 
Tue Jan  6 15:06:48 2015 [notice] hyalite: Service postfix was restarted