1. Changed definition of IsDetached property in SR.cs: SR is detached when it has no PBDs or when all its PBDs are unplugged.
2. Added bool HasPBDs property in SR.cs (replaced previous IsDetached property definition).
3. Reviewed all usages of sr.IsDetached property.
Signed-off-by: Adrian Jachacy <Adrian.Jachacy@citrix.com>