fetchmail: Update to version 6.5.4

fetchmail: Update to version 6.5.4

- Update from version 6.5.3 to 6.5.4
- Update of rootfile not required
- Changelog
    6.5.4
      BUGFIXES:
	* socket: avoid crash when writing to a socket without SSL/TLS fails.
	  Reported by Andrea Venturoli via mailing list, fixes #71.
	* wolfSSL support: avoid fetchmail.c compilation failure in certain
	  configurations of wolfSSL (for instance, on FreeBSD's wolfssl-5.8.0_1
	  package), OpenSSL_version enables a newer 1.1.x compat API that passes its
	  argument to a wolfSSL API, with OPENSSL_DIR and OPENSSL_ENGINES_DIR, causing
	  related compiler failures.
	  See <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=287435>.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>