Revert "FIB: optimise for src memory allocations"

This reverts commit 84517cfd1508f6da24937f310f7fffe752f22584.

Change-Id: Ic7eeffa2ed4607d3d653f34b93c20c833c789ee1
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet/fib/fib_entry_src_mpls.c b/src/vnet/fib/fib_entry_src_mpls.c
index f95ca65..f80d42a 100644
--- a/src/vnet/fib/fib_entry_src_mpls.c
+++ b/src/vnet/fib/fib_entry_src_mpls.c
@@ -181,6 +181,13 @@
     .fesv_format = fib_entry_src_mpls_format,
     .fesv_set_data = fib_entry_src_mpls_set_data,
     .fesv_get_data = fib_entry_src_mpls_get_data,
+    /*
+     * .fesv_fwd_update = fib_entry_src_mpls_fwd_update,
+     *  When the forwarding for the IP entry is updated, any MPLS chains
+     * it has created are also updated. Since the MPLS entry will have already
+     * installed that chain/load-balance there is no need to update the netry
+     * FIXME: later: propagate any walk to the children of the MPLS entry. for SR
+     */
 };
 
 void