new upstream release (2.4.28)
    
    - upstream changes:
      - server: support for delta-syncrepl in multi master replication
      - server: add experimental backend - MDB
      - server: dynamic configuration for passwd, perl, shell, sock,
        and sql backends
      - server: support passwords in APR1
      - library: support for Wahl (draft)
      - a lot of bugfixes
    - remove patches which were merged upstream