Remove instance colors
Remove instance colors

We have hardcoded instance colors that show up in knife ec2 server list.
The colors are hard coded to incredibly old instance types.  We *could*
update this for the current instance types, but it would be outdated in
another quarter.  It's probably better to just remove this functionality
since it's confusing as-is.

tas50/knife-ec2,juliandunn/knife-ec2,chef/knife-ec2,MsysTechnologiesllc/knife-ec2,ClogenyTechnologies/knife-ec2,cloudant/knife-ec2,chef/knife-ec2,MsysTechnologiesllc/knife-ec2