Fixed null str returned for incorrect parameter

For resources like ResourceGroup, the output parameters are not
validated during stack creation. When a stack has an output parameter
which accesses an incorrect attribute of a resource, the output-show
command returns the string 'null'.
This fix instead returns an error indicating the incorrect attribute
being accessed.

Change-Id: I51eea4738bfefb35644a384ec6d4e9176c8f2e26
Closes-bug: #1368041
Updated from global requirements

Change-Id: Id5292a78f9c1aa90ad3da2b2b87aa1ffa668f2f8
Remove extraneous vim editor configuration comments

Change-Id: Ib2635e29c6c3259b270e4a046a1afea22582ceb8
Partial-Bug: #1229324
Merge "Fixed null str returned for incorrect parameter"
Merge "Updated from global requirements"