add sha info to ChangeTracker debug output
add sha info to ChangeTracker debug output

Add the sha info to the debug output from the change tracker so it is
easier to follow why changes are being recorded.

Change-Id: If1fae2002cb06d87b61491ecec95599b793ae357
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

openstack/reno