In some cases, there is no information about resource and
section, where Property error raised. This patch improves
StackValidationFailed msg, so this msg look like "Property
error : resource_name.section_name.key_name: error_msg", where
section_name is section, where Property error raised, e.g.
'update_policy'.
Cherry-picked from 3ad4614276
Change-Id: Iab2a6acdec254b39983de420ab03f994cff48d89
Closes-bug: #1358512