nat: use SVR

Remove NAT's implementation of shallow virtual reassembly with
corresponding CLIs, APIs & tests. Replace with standalone shallow
virtual reassembly provided by ipX-sv-reass* nodes.

Type: refactor
Change-Id: I7e6c7487a5a500d591f6871474a359e0993e59b6
Signed-off-by: Klement Sekera <ksekera@cisco.com>
diff --git a/src/vnet/ip/ip4_packet.h b/src/vnet/ip/ip4_packet.h
index 79cf22c..1d3607e 100644
--- a/src/vnet/ip/ip4_packet.h
+++ b/src/vnet/ip/ip4_packet.h
@@ -196,13 +196,13 @@
 
 #define IP4_ROUTER_ALERT_OPTION 20
 
-always_inline int
+always_inline u16
 ip4_get_fragment_offset (const ip4_header_t * i)
 {
   return clib_net_to_host_u16 (i->flags_and_fragment_offset) & 0x1fff;
 }
 
-always_inline int
+always_inline u16
 ip4_get_fragment_more (const ip4_header_t * i)
 {
   return clib_net_to_host_u16 (i->flags_and_fragment_offset) &