Add a number of fixes for bugs reported upstream
    
    - Avoid spinning proftpd process if read(2) returns EAGAIN (bug 3639)
    - SITE CPFR/CPTO does not update quota tally (bug 3641)
    - Segfault in mod_sql_mysql if "SQLAuthenticate groupsetfast" used (bug 3642)
    - Disable signal handling for exiting session processes (bug 3644)
    - Ensure that SQLNamedConnectInfos with PERSESSION connection policies are
      opened before chroot (bug 3645)
    - MaxStoreFileSize can be bypassed using REST/APPE (bug 3649)
    - Fix TCPAccessSyslogLevel directive (bug 3652)
    - Segfault with "DefaultServer off" and no matching server for incoming IP
      address (bug 3653)