Refactor some patches out of redis.spec
    
    For cases where we have two ways of doing one thing (using
    a patch or sed-based modification of files), rework these
    such that we're only using one method.  Allows several of
    the patches to be dropped.
    
    Described in https://github.com/antirez/redis/issues/1417
    is a method for allowing integration/replication-psync to
    be reliably run - start using it, and drop the patch that
    was disabling that test.
    
    Other small side-effects of this commit:
    - the build warning about "jemalloc not found" is fixed;
    - CFLAGS additions are now consistently handled (for deps
      as well) - using the upstream-provided mechanism for
      compiler flag propogation.