*: call if_init()/if_terminate() from vrf_init()/vrf_terminate()

*: call if_init()/if_terminate() from vrf_init()/vrf_terminate()

Later, an interface will belong to a specific VRF, and the interface
initialization will be a part of the VRF initialization. So now call
if_init() from vrf_init(), and if_terminate() from vrf_terminate().

Daemons have the according changes:
- if if_init() was called or "iflist" was initialized, now call
  vrf_init() instead;
- if if_terminate() was called or "iflist" was destroyed, now call
  vrf_terminate() instead.

Signed-off-by: Feng Lu <lu.feng@6wind.com>
Reviewed-by: Alain Ritoux <alain.ritoux@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Vincent JARDIN <vincent.jardin@6wind.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Conflicts:
	bgpd/bgp_main.c
	pimd/pim_iface.c
	pimd/pim_iface.h
	pimd/pim_main.c
	pimd/pimd.c