package/exim: security bump to version 4.92.1

package/exim: security bump to version 4.92.1

Fixes CVE-2019-13917:
http://www.exim.org/static/doc/security/CVE-2019-13917.txt

https://github.com/Exim/exim/commit/d185889f47b9b27088e777f7d382295c51271586
added new code to "Prebuild the data structure for builtin macros".

This function needs a host-built binary called macro_predef, it depends
on host-berkeleydb, host-pcre and optionally on host-openssl.

With an openssl-enabled exim the host build of macro_predef will fail
if host-openssl is missing:

/usr/bin/gcc -DMACRO_PREDEF macro_predef.c
In file included from hash.h:14,
                 from exim.h:485,
                 from macro_predef.c:11:
sha_ver.h:37:12: fatal error: openssl/ssl.h: No such file or directory

because macro_predef also has the an optional dependency on openssl:
https://github.com/Exim/exim/blob/exim-4.92%2Bfixes/src/src/macro_predef.c#L130

Removed patches applied upstream:
0004: https://github.com/Exim/exim/commit/98913c8ea2be5188dd22ec652da1182017e8edb7
0005: https://github.com/Exim/exim/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1
0007: https://github.com/Exim/exim/commit/7ea1237c783e380d7bdb86c90b13d8203c7ecf26#diff-58af16fe62ea674adf1730edc078d175R6243

Added patch to fix uClibc build.

Added license hash, switched _SITE to https.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>