vpp_papi.py: Change VppEnum from explicit metaclass to metaclass wrapper/decorator.
vpp_papi.py: Change VppEnum from explicit metaclass to metaclass wrapper/decorator.

Change-Id: Iab41bb972e3c7ec005a1a13d5a25f654ae8c3932
Signed-off-by: Paul Vinciguerra <b92f79aabe4c9c18085c7347110a52af0898a0ef@vinciconsulting.com>

FDio/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,chrisy/vpp