Drop zlib-1.2.7-z-block-flush.patch
    
    This brings unnecessary upstream incompatibility and API change
    (it changes priority of different flush types in some cases).
    
    The original reason for this patch was rhbz#844791, which has been
    later worked-around in tigervnc anyways (b5822f32ab5043b4e).
    
    Zlib upstream fixed the original issue by commit
    c661c374e8df43365738daa09f4390d61bc57f08, which is for some time
    available in Fedora's zlib (1.2.7.1+).
    
    Version: 1.2.11-1
    Resolves: rhbz#1417355