core: Cleanup of Vnic and Disk hotplug

This change clean the obsolete code of disk and NIC hotplug,
because the code was migrated from database to the osinfo file.

Change-Id: I8c38a8ecbbc56fc8ef70c6e45732225ce96ba1f0
Signed-off-by: Gustavo Pedrosa <gustavo.pedrosa@eldorado.org.br>