GUI-1294, GUI-1310 Disable the VPC subnet select options if they are in the same zone as th...

...e selected VPC subnets in the scaling group wizard and detail page.
https://eucalyptus.atlassian.net/browse/GUI-1294
https://eucalyptus.atlassian.net/browse/GUI-1310
The line has been updated to use .format() method.