lib, bgpd, tests: Refactor FILTER_X in zebra.h

lib/zebra.h has FILTER_X #define's.  These do not belong there.
Put them in lib/filter.h where they belong.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index 36fd263..efbd8db 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -30,6 +30,7 @@
 #include "log.h"
 #include "memory.h"
 #include "hash.h"
+#include "filter.h"
 
 #include "bgpd/bgpd.h"
 #include "bgpd/bgp_advertise.h"