Revert "lib: wrong #define used for IPV6_MINHOPCOUNT"

This reverts commit 54b88cac24f335414caa875b390d2d78ff4bf9e0.

Unfortunately, this breaks the build on systems where linux/in6.h and
netinet/in.h can't both be included, such as Ubuntu 14.04 and Debian
Jessie.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/lib/sockunion.c b/lib/sockunion.c
index 8f3540d..c7315f2 100644
--- a/lib/sockunion.c
+++ b/lib/sockunion.c
@@ -29,10 +29,6 @@
 #include "log.h"
 #include "jhash.h"
 
-#if defined(HAVE_LINUX_IN6_H)
-#include <linux/in6.h>
-#endif
-
 #ifndef HAVE_INET_ATON
 int
 inet_aton (const char *cp, struct in_addr *inaddr)
@@ -510,13 +506,13 @@
       return ret;
     }
 #endif /* IP_MINTTL */
-#ifdef IPV6_MINHOPCOUNT
+#ifdef IPV6_MINHOPCNT
   if (family == AF_INET6)
     {
-      int ret = setsockopt (sock, IPPROTO_IPV6, IPV6_MINHOPCOUNT, &minttl, sizeof(minttl));
+      int ret = setsockopt (sock, IPPROTO_IPV6, IPV6_MINHOPCNT, &minttl, sizeof(minttl));
       if (ret < 0)
 	  zlog (NULL, LOG_WARNING,
-		"can't set sockopt IPV6_MINHOPCOUNT to %d on socket %d: %s",
+		"can't set sockopt IPV6_MINHOPCNT to %d on socket %d: %s",
 		minttl, sock, safe_strerror (errno));
       return ret;
     }