guix system: Gracefully handle incomplete commands.

Fixes <http://bugs.gnu.org/21451>.
Reported by Steve Sprang <steve.sprang@gmail.com>.

* guix/scripts/system.scm (guix-system)[option-arguments]: Error out
  when ACTION is #f.

doc: Use the recommended Scheme format.

Apply the recommended formatting rules from '.dir-locals.el' to the
examples in the manual in order to fulfill it's purpose of being a
reference.

* doc/package-hello.scm: Indent it.
* doc/guix.texi (Defining Packages, Version Numbers): Likewise.
* gnu/packages/base.scm (hello): Be consistent with the manual.

gnu: Add bio-locus.

* gnu/packages/bioinformatics.scm (bio-locus): New variable.

Revert "gnu: Add bio-locus."

This reverts commit b429c4fbb06299ce10ecc113a7818bf777c63a6e.

gnu: Add bio-locus.

* gnu/packages/bioinformatics.scm (bio-locus): New variable.

gnu: system: Add Linux container module.

* gnu/system/linux-container.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* gnu/system.scm: Export 'operating-system-etc-directory',
  'operating-system-boot-script', 'operating-system-locale-directory', and
  'file-union'.
  (operating-system-boot-script): Add #:container? keyword argument.
  (operating-system-activation-script): Add #:container?  keyword argument.
  Don't call 'activate-firmware' or 'activate-ptrace-attach' when activating a
  container.

build: ruby: Add support for tarball and directory sources.

Previously, the Ruby build system only knew how to work with gem archives,
which made it difficult to build unreleased gems from a Git repository or
released gems in tarball form.

* gnu/build/ruby-build-system.scm (gnu:unpack, gem-archive?): New procedures.
  (unpack): Use GNU build system unpack phase for non-gem sources.
  (build): Rebuild the gemspec iff the source is a gem archive.
* guix.texi ("ruby-build-system"): Mention that tarballs and directories are
  acceptable.

gnu: Add python-oslo.utils.

* gnu/packages/openstack.scm (python-oslo.utils, python2-oslo.utils): New variables.

gnu: Add python-debtcollector.

* gnu/packages/openstack.scm (python-debtcollector,
  python2-debtcollector): New variables.

gnu: Add python-monotonic.

* gnu/packages/python.scm (python-monotonic, python2-monotonic): New variables.

gnu: Add python-iso8601.

* gnu/packages/python.scm (python-iso8601, python2-iso8601): New variables.

gnu: Add python-wrapt

* gnu/packages/python.scm (python-wrapt, python2-wrapt): New variables.

gnu: Add python-oslo.config.

* gnu/packages/openstack.scm (python-oslo.config, python2-oslo.config): New variables.

gnu: Add python-stevedore.

* gnu/packages/openstack.scm (python-stevedore, python2-stevedore): New variables.

gnu: Add python-netaddr.

* gnu/packages/python.scm (python-netaddr, python2-netaddr): New variables.

gnu: Add cvs-fast-export.

* gnu/packages/version-control.scm (cvs-fast-export): New variable.

gnu: gnupg: Update to 2.1.8.

* gnu/packages/gnupg.scm (gnupg): Update to 2.1.8.

gnu: cpio: Upgrade to 2.12.

* gnu/packages/cpio.scm (cpio): Update to 2.12.
  [source]: Remove 'patches' field.
* gnu/packages/patches/cpio-CVE-2014-9112-pt1.patch,
  gnu/packages/patches/cpio-CVE-2014-9112-pt2.patch,
  gnu/packages/patches/cpio-CVE-2014-9112-pt3.patch,
  gnu/packages/patches/cpio-CVE-2014-9112-pt4.patch,
  gnu/packages/patches/cpio-CVE-2014-9112-pt5.patch,
  gnu/packages/patches/cpio-fix-symlink-bad-length-test.patch: Remove.
* gnu-system.am (dist_patch_DATA): Remove.

gnu: tiled: Update to 0.13.1.

* gnu/packages/game-development.scm (tiled): Update to 0.13.1.

gnu: redis: Update to 3.0.4

* gnu/packages/databases.scm (redis): Update to 3.0.4.