pluto: Make sure connection name is null-terminated during DPD restart.

src/pluto/ipsec_doi.c

@@ -5851,6 +5851,7 @@ dpd_timeout(struct state *st)
 
 		/* caching the connection name before deletion */
 		strncpy(cname, c->name, BUF_LEN);
+		cname[BUF_LEN-1] = '\0';
 
 		if (c->kind == CK_INSTANCE)
 		{