Update .gitignore location of vdsm-api.html changed

Change-Id: Ib030382a0b078ca8f8d21bba81cd120965f4986c
Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/28881
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>