build.sh: Replace '-name' with '--name'

Docker has adopted GNU-style long options with v0.8.0 :) [1]:

  First step toward getopt style flags:

  As we keep compatibility with flags like -dns we can't have -i -t ->
  -it but at least - and -- are now correct.

Strangely, I the short form doesn't always work for me anymore:

  $ docker run -name my-container -hostname my-container wking/gentoo /bin/bash
  flag provided but not defined: -hostname

Note that the -name works fine but the newer --hostname requires the
'--' form.

[1]: https://github.com/dotcloud/docker/pull/3322
     e71dbf4 (update commands.go, 2013-12-23)