Add rsync and update libstdc++ version

• Add rsync because we need it since 1bc32516.

• Update the libstdc++ version.

• The redoxer exec true step is still failing because:

  • The dash package is not in the repository.

  • I think that dash is the default shell sh and it is used in the 20_redoxer init script. I see the following in the console if I try to build redoxer without the dash package:

    ## running redoxer-env ##
    init: failed to execute 'sh /etc/redoxer-env': No such file or directory (os error 2)