mappkgname: libsexplib-camlp4 now defines a proper -dev package

Previously we artificially renamed ocaml-sexplib to be a -dev
package on Debian because the package naming rules required it.
Now that ocaml-sexplib defines a proper devel package this is not
needed.

Signed-off-by: Euan Harris <euan.harris@citrix.com>
ocaml-tapctl: Add devel package dependency needed by Debian build

Signed-off-by: Euan Harris <euan.harris@citrix.com>