ospf6d/ospfd: refactor some common defines

Rearranging common defs and structures for use betweeen OSPFv2 and
OSPFv3.  Created a new file called libospf.h under lib directory to
hold defines that are common between OSPFv2 and OSPFv3 code bases.

[DL: split of defines refactor from timer refactor]
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/ospf6d/ospf6_area.c b/ospf6d/ospf6_area.c
index 9934e6b..2d20e62 100644
--- a/ospf6d/ospf6_area.c
+++ b/ospf6d/ospf6_area.c
@@ -401,6 +401,7 @@
     }
 
   ospf6_route_remove (range, oa->range_table);
+
   return CMD_SUCCESS;
 }