Do not reuse forwarding metadata post mirroring

A mirror action needs its own forwarding metadata since the forwarding
parameeters that are used for mirroring will be different from those
that are used for packet forwarding. In this particular case, the vrf
to which the packets are mirrored are different from the vrf to which
packets need to be classified, and hence the packets were dropped in the
flow module with no source route as the drop reason.

Change-Id: I21930818a5cdec560818acb79f671ce29ac8bc85
Closes-BUG: #1552101

dp-core/vr_datapath.c

@@ -547,7 +547,7 @@ unsigned int
 vr_virtual_input(unsigned short vrf, struct vr_interface *vif,
                  struct vr_packet *pkt, unsigned short vlan_id)
 {
-    struct vr_forwarding_md fmd;
+    struct vr_forwarding_md fmd, mfmd;
 
     vr_init_forwarding_md(&fmd);
     fmd.fmd_vlan = vlan_id;
@@ -559,7 +559,8 @@ vr_virtual_input(unsigned short vrf, struct vr_interface *vif,
     }
 
     if (vif->vif_flags & VIF_FLAG_MIRROR_RX) {
-        fmd.fmd_dvrf = vif->vif_vrf;
+        mfmd = fmd;
+        mfmd.fmd_dvrf = vif->vif_vrf;
         vr_mirror(vif->vif_router, vif->vif_mirror_id, pkt, &fmd);
     }