openshift.ks: Clean up need_jboss*_repo

Delete need_jbosseap_repo and need_jbossews_repo, which are not used
after commit a027ccf8d421ecbee5d5e4b4985f2a61d5019cf2.

Rename need_jbosseap_cartridge_repo to need_jbosseap_repo.
openshift.ks: Add CONF_CARTRIDGES

Add the following setting, as documented in the script:

cartridges / CONF_CARTRIDGES
  Comma-separated selections from the following:
    all - all cartridges;
    standard - all cartridges except for JBossEWS or JBossEAP;
    cron - embedded cron support;
    diy - do-it-yourself cartridge;
    haproxy - haproxy support for scalable apps;
    jbossews - JBossEWS support;
    jobsseap - JBossEAP support;
    jboss - alias for jbossews and jbosseap;
    jenkins - Jenkins client and server for continuous integration;
    mysql - MySQL;
    nodejs - NodeJS;
    perl - mod_perl support;
    php - PHP support;
    postgresql - PostgreSQL support;
    postgres - alias for postgresql;
    python - Python support;
    ruby - Ruby Rack support running on Phusion Passenger.

  You may prepend a minus sign '-' to any one of the above to negate it.
  For example, all,-jbossews enables all cartridges except for jbossews.

  You may also specify a package name; any selection that is not in the above
  list will be assumed to be a package name and will be added to (or removed
  from) the list of packages to install, verbatim.

  Selections are read from left to right.  For example, all,-jboss,jbossews
  enables all cartridges except for JBoss cartridges, except for JBossEWS (so
  JBossEWS _will_ be enabled but JBossEAP will _not_ be enabled).  However,
  all,jbossews,-jboss would install all cartridges except for JBoss cartridges
  (so neither JBossEWS nor JBossEAP will be installed).

  If JBossEAP support is selected, this script will ensure that the required
  channels or repositories are enabled.

  Default: standard

Document no_jbossews / CONF_NO_JBOSSEWS and no_jbosseap / CONF_NO_JBOSSEAP
as deprecated.

parse_cartridges: New function that parses CONF_CARTRIDGES, sets
install_pkgs for use by install_cartridges, sets CONF_NO_JBOSSEAP for
configure_repos, and prints a deprecation warning if CONF_NO_JBOSSEWS or
CONF_NO_JBOSSEAP has been specified by the user.

install_cartridges: Modify accordingly.

set_defaults: Assign cartridges the default value of 'standard'.

do_all_actions: Call parse_cartridges before configure_repos and
install_rpms (which calls install_cartridges) so that parse_cartridges
will set CONF_NO_JBOSSEAP for configure_repos and install_pkgs for
install_cartridges.

This commit fixes bug 1055824.
Merge pull request #271 from Miciah/openshift.ks-add-CONF_CARTRIDGES

openshift.sh: Add CONF_CARTRIDGES
Initial code for VM
Added basic RHEL VM setup functionality