Improve make-rhat-patches.sh for local development
    
    make-rhat-patches.sh had everything hard coded and didn't update spec file so it
    was hard to use for local selinux-policy development. This patch doesn't change
    default behavior, but makes this script configurable using environmental
    variables and one option.
    
    Usage:
    
    If you want to change location of repositories set the following variables:
    
    REPO_SELINUX_POLICY
      selinux-policy repository
    
    REPO_SELINUX_POLICY_BRANCH
      selinux-policy repository branch
    
    REPO_SELINUX_POLICY_CONTRIB
      selinux-policy repository
    
    REPO_SELINUX_POLICY_CONTRIB_BRANCH
      selinux-policy-contrib repository branch
    
    REPO_CONTAINER_SELINUX
      container-selinux repository
    
    If you want to use locally created tarball (and don't download tarballs from
    github), use '-l' option.
    
    Example:
    
      export REPO_SELINUX_POLICY=~/devel/local/selinux-policy.git
            export REPO_SELINUX_POLICY_BRANCH=WIP-my-new-fix
            export REPO_SELINUX_POLICY_CONTRIB=~/devel/local/selinux-policy-contrib.git
            export REPO_SELINUX_POLICY_CONTRIB_BRANCH=WIP-some-contrib-fix
            export REPO_CONTAINER_SELINUX=~/devel/local/container-selinux.git
    
      ./make-rhat-patches.sh -l