oasis: Remove explicit ocaml requirement - it can be inferred

Signed-off-by: Euan Harris <euan.harris@citrix.com>
oasis: Use traditional build entry points

Signed-off-by: Euan Harris <euan.harris@citrix.com>
oasis: Get rid of duplicate definition of OCAMLFIND_DESTDIR

Signed-off-by: Euan Harris <euan.harris@citrix.com>
ocamlify: Tidy up spec file

Signed-off-by: Euan Harris <euan.harris@citrix.com>
ocamlmod: Tidy up spec file

Signed-off-by: Euan Harris <euan.harris@citrix.com>
ocaml-nbd: Tidy up spec file

Signed-off-by: Euan Harris <euan.harris@citrix.com>
Merge pull request #396 from euanh/build-improvements

Improve spec files for oasis and its dependencies