CLOUDSTACK-6859:Management Server PermGen run out of memory after some
time due to class leak.
CLOUDSTACK-6669: Fix support resize in usage server

Signed-off-by: Sebastien Goasguen <runseb@gmail.com>
Cleanup of Xen and XenServer terms. Cloned xen plugin creating a xenserver plugin, then removed xen plugin

Signed-off-by: Tim Mackey <tmackey@gmail.com>
Signed-off-by: Sebastien Goasguen <runseb@gmail.com>