add libffi-devel to development packages

this is now needed to solve:

    An error occurred while installing fiddle (1.1.8), and Bundler cannot continue.

    In Gemfile:
      gettext_i18n_rails_js was resolved to 1.4.0, which depends on
        gettext was resolved to 3.5.2, which depends on
          locale was resolved to 2.1.5, which depends on
            fiddle

As `fiddle` needs `libffi-devel` to build.

Author: evgeni

development/roles/foreman_development/defaults/main.yaml

@@ -157,6 +157,7 @@ foreman_development_packages:
   - libxml2-devel
   - libxslt-devel
   - libcurl-devel
+  - libffi-devel
   - gcc-c++
   - make
   - rubygem-bundler