bgpd: fix ecommunity_token initialiser

This pulls up ecommunity_token_unknown to be the first enum value (at
0), and uses that as initialiser to get rid of the uninitialised use
warning.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/bgpd/bgp_ecommunity.c b/bgpd/bgp_ecommunity.c
index 482e76b..04957d4 100644
--- a/bgpd/bgp_ecommunity.c
+++ b/bgpd/bgp_ecommunity.c
@@ -281,10 +281,10 @@
 /* Extended Communities token enum. */
 enum ecommunity_token
 {
+  ecommunity_token_unknown = 0,
   ecommunity_token_rt,
   ecommunity_token_soo,
   ecommunity_token_val,
-  ecommunity_token_unknown
 };
 
 /* Get next Extended Communities token from the string. */
@@ -511,7 +511,7 @@
 ecommunity_str2com (const char *str, int type, int keyword_included)
 {
   struct ecommunity *ecom = NULL;
-  enum ecommunity_token token;
+  enum ecommunity_token token = ecommunity_token_unknown;
   struct ecommunity_val eval;
   int keyword = 0;