simplenode.reltool.config: use default sys-level mod_cond setting

As discussed here
http://erlang.org/pipermail/erlang-questions/2012-December/071135.html
change the reltool spec to use the default sys-level mod_cond setting.

priv/templates/simplenode.reltool.config

@@ -19,7 +19,6 @@
        {boot_rel, "{{nodeid}}"},
        {profile, embedded},
        {incl_cond, derived},
-       {mod_cond, derived},
        {excl_archive_filters, [".*"]}, %% Do not archive built libs
        {excl_sys_filters, ["^bin/.*", "^erts.*/bin/(dialyzer|typer)",
                            "^erts.*/(doc|info|include|lib|man|src)"]},