Merge pull request #47 from CraigFe/remove-dune-build-directive

opam: remove the 'build' directive on dune dependency

Author: hannesm

mirage-net-unix.opam

@@ -9,7 +9,7 @@ doc: "https://mirage.github.io/mirage-net-unix/"
 bug-reports: "https://github.com/mirage/mirage-net-unix/issues"
 depends: [
   "ocaml" {>= "4.04.2"}
-  "dune" {build & >= "1.0"}
+  "dune" {>= "1.0"}
   "cstruct" {>= "1.7.1"}
   "cstruct-lwt"
   "lwt" {>= "2.4.3"}