Add object_type to tuskar storage exceptions
Add object_type to tuskar storage exceptions

This makes it easier to see which object is causing an issue and can be
useful when working in batch operations such as with a plan when it will
edit the plan, master template and environment file.

Change-Id: I5fb1a379f43b0a4e1e2e71344c665e129b0c7457

rdo-management/tuskar,rdo-management/tuskar,rdo-management/tuskar