Fix unefficient netlink socket creation for all existing vrf
Fix unefficient netlink socket creation for all existing vrf

Fixes: #149 - ofp_create_ns_socket creates unnecessary children
processes

Fix the issue by creating only one child process to create netlink
sockets for all existing vrf

Signed-off-by: Dapeng Liu <2a4cd463150ae38e66022a116d1b4d46734be600@linaro.org>
Reviewed-by: Sorin Vultureanu <8013ba55f8675034bc2ab0d6c3a1c9650437ca36@enea.com>

TolikH/ofp,OpenFastPath/ofp,TolikH/ofp,OpenFastPath/ofp,TolikH/ofp,OpenFastPath/ofp,OpenFastPath/ofp