Thread_index for thread0 in vlib_global_main not initialised

Change-Id: Ie49ee865b197e8fe7bba170c115a4ccbf1013e5f
Signed-off-by: Keith Burns (alagalah) <alagalah@gmail.com>

src/vlib/unix/main.c

@@ -626,6 +626,7 @@ vlib_unix_main (int argc, char *argv[])
   vlib_thread_stack_init (0);
 
   __os_thread_index = 0;
+  vm->thread_index = 0;
 
   i = clib_calljmp (thread0, (uword) vm,
 		    (void *) (vlib_thread_stacks[0] +