merge and conditionalize some EL6isms
    
    - undo rename from krb5-pkinit-openssl to krb5-pkinit on EL6
    - version the Obsoletes: on the krb5-pkinit-openssl to krb5-pkinit rename
    - reintroduce the init scripts for non-systemd releases
    - forward-port %%{_?rawbuild} annotations from EL6 packaging