Don't store attributes if resource not stored
Don't store attributes if resource not stored

If stack-show is called at an inopportune moment in convergence, we can
attempt to store the attributes of a resource that isn't actually in the
database.  This causes occasional gate failures due to an assert.

Closes-Bug: #1701569
Change-Id: I50de08ae6b40958781ef4223c82a5c195b0757bf

openstack/heat,openstack/heat,noironetworks/heat,noironetworks/heat