Auto merge of #933 - raphlinus:ipv6_fuchsia, r=alexcrichton

Add IPV6_UNICAST_HOPS to fuchsia module

Recent change #925 added constants for IPV6 multicast, but seems to have inadvertently left off IPV6_UNICAST_HOPS from the fuchsia module.

Fixes #932

Author: bors

src/fuchsia/mod.rs

@@ -1486,6 +1486,7 @@ pub const IP_HDRINCL: ::c_int = 3;
 pub const IP_ADD_MEMBERSHIP: ::c_int = 35;
 pub const IP_DROP_MEMBERSHIP: ::c_int = 36;
 pub const IP_TRANSPARENT: ::c_int = 19;
+pub const IPV6_UNICAST_HOPS: ::c_int = 16;
 pub const IPV6_MULTICAST_IF: ::c_int = 17;
 pub const IPV6_MULTICAST_HOPS: ::c_int = 18;
 pub const IPV6_MULTICAST_LOOP: ::c_int = 19;