Initialize gc_mark_timestamp to zero to avoid garbage values.
Initialize gc_mark_timestamp to zero to avoid garbage values.

Change-Id: Ib3f030e906da9828fdad27e19b9efb0c349b0734
Signed-off-by: Brian Nesbitt <568d48993be24454667364c95514fe0b67e69e7e@owmobility.com>

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