VMware: remove unused parameters in imagecache

Trivial patch to remove some unused parameters in
timestamp_cleanup().

Change-Id: Id3c6e8c6c504591fdf09e8871cf3358d265a678c
Add testing for hooks

Partially implements: bp instance-network-info-hook

Change-Id: Ie7cfcf70ff39f1273d97b17788c2e4e0f9fc437f
Merge "Add testing for hooks"
Merge "VMware: remove unused parameters in imagecache"