Drop Requires on python-dogpile-core (#1422716).
    
    Also:
    - Provide and obsolete python-dogpile-core.
    - Replace the description with upstream's new description, and make
      it a global.
    - Make the summary a global.
    - Rename python-dogpile-cache to python2-dogpile-cache.
    - Use the license macro.
    
    Signed-off-by: Randy Barlow <randy@electronsweatshop.com>