FIB table add/delete API

part 2;
  - this adds the code to create an IP and MPLS table via the API.
  - but the enforcement that the table must be created before it is used is still missing, this is so that CSIT can pass.

Change-Id: Id124d884ade6cb7da947225200e3bb193454c555
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet/mfib/mfib_entry.c b/src/vnet/mfib/mfib_entry.c
index 804e10a..2302b9a 100644
--- a/src/vnet/mfib/mfib_entry.c
+++ b/src/vnet/mfib/mfib_entry.c
@@ -334,6 +334,17 @@
     return (bsrc);
 }
 
+int
+mfib_entry_is_sourced (fib_node_index_t mfib_entry_index,
+                       mfib_source_t source)
+{
+    mfib_entry_t *mfib_entry;
+
+    mfib_entry = mfib_entry_get(mfib_entry_index);
+
+    return (NULL != mfib_entry_src_find(mfib_entry, source, NULL));
+}
+
 static void
 mfib_entry_src_flush (mfib_entry_src_t *msrc)
 {