isisd: fix minor & vs. && mix-up

apparently we were displaying all IPv6 reachabilities as external.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/isisd/isis_lsp.c b/isisd/isis_lsp.c
index 83dc604..4c09e79 100644
--- a/isisd/isis_lsp.c
+++ b/isisd/isis_lsp.c
@@ -950,7 +950,7 @@
       memcpy (in6.s6_addr, ipv6_reach->prefix,
 	      PSIZE (ipv6_reach->prefix_len));
       inet_ntop (AF_INET6, &in6, (char *)buff, BUFSIZ);
-      if ((ipv6_reach->control_info &&
+      if ((ipv6_reach->control_info &
 	   CTRL_INFO_DISTRIBUTION) == DISTRIBUTION_INTERNAL)
 	vty_out (vty, "  Metric      : %-8d IPv6-Internal : %s/%d%s",
 		 ntohl (ipv6_reach->metric),