Updated gnupg21 to 2.1.21.

Noteworthy changes in version 2.1.21 (2017-05-15)
-------------------------------------------------

  * gpg,gpgsm: Fix corruption of old style keyring.gpg files.  This
    bug was introduced with version 2.1.20.  Note that the default
    pubring.kbx format was not affected.

  * gpg,dirmngr: Removed the skeleton config file support.  The
    system's standard methods for providing default configuration
    files should be used instead.

  * w32: The Windows installer now allows installion of GnuPG without
    Administrator permissions.

  * gpg: Fixed import filter property match bug.

  * scd: Removed Linux support for Cardman 4040 PCMCIA reader.

  * scd: Fixed some corner case bugs in resume/suspend handling.

  * Many minor bug fixes and code cleanup.

(wiz)