Fix longstanding next-frame clone bug
Fix longstanding next-frame clone bug

Do not propagate flags into cloned vlib_next_frame_t's.
vlib_next_frame_init(...) sets nf->frame_index to ~0. If it turns out
that the original flags include VLIB_FRAME_IS_ALLOCATED, the wheels
fall off. And so on.

Change-Id: I8de18653acfcc8eb20cee36f4eb5b9e82234f21b
Signed-off-by: Dave Barach <bfcdf3e6ca6cef45543bfbb57509c92aec9a39fb@barachs.net>

FDio/vpp,GabrielGanne/vpp-flowtable,GabrielGanne/vpp-flowtable,chrisy/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,milanlenco/vpp,muharif/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,muharif/vpp,milanlenco/vpp,muharif/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,vpp-dev/vpp,milanlenco/vpp,muharif/vpp,milanlenco/vpp,vpp-dev/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,milanlenco/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,muharif/vpp,FDio/vpp,milanlenco/vpp,muharif/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,vpp-dev/vpp,GabrielGanne/vpp-flowtable