Update sylpheed-devel to 2.1.4. Main changes/bugfixes are:

Update sylpheed-devel to 2.1.4.  Main changes/bugfixes are:
    o The IMAP4 parser was fixed so that it can handle literals in
      response.
    o A bug that caused crashes on receive if Date header has
      abnormal time was fixed.
    o Sylpheed will not close anymore even if the tray icon is closed.
    o The directory with multiple hierarchy can be specified when
      creating a new mailbox.
    o Error messages are now output to the log window and the log file.
    o The 'Create filter rule' menu was brought back in the context
      menu.
    o The display of the property of top folders was enabled.
    o The support of environment-dependent Japanese characters was
      enhanced