vlib: properly configure main thread's core id
vlib: properly configure main thread's core id

Prior to this patch, the main thread's core id was
always reported as 0.
This patch makes a call to vlib_get_thread_core_socket() on
the main thread so that its core id is set properly.

Type: fix
Fixes: 5d64c7868f67749a6c99eb4ee5998b518ab6c71c

Change-Id: I019cb95eec031da25197e48d956038c4bd6b5040
Signed-off-by: Jon Loeliger <2c20cf3f4bac0d9467d3fe2c932e4d1e1bc1f44c@netgate.com>

chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,FDio/vpp