This change updates the deployment serializer for the test vm data to
pass the glance properties as a hash that can be used by the
glance_image provider rather than using the glance_properties string
that is currently in place. The glance_properties string should be
considered deprecated and anything that uses it should switch to the
properties hash.
DocImpact: glance_properties string provided as part of the
test_vm_image hiera data is deprecated in favor of the properties hash
provided by this change
Change-Id: I79a9b20d89ae00a7ceaa24c4ce655cbd16972c30
Partial-Bug: #1566434
85e9a608f4