www/nginx-devel: update from 1.21.1 to 1.21.2.

While I'm here, fix build of the third-party ajp module by changing
a distribution point.

<Changelog>

*) Change: now nginx rejects HTTP/1.0 requests with the

"Transfer-Encoding" header line.

*) Change: export ciphers are no longer supported.

*) Feature: OpenSSL 3.0 compatibility.

*) Feature: the "Auth-SSL-Protocol" and "Auth-SSL-Cipher" header lines

are now passed to the mail proxy authentication server.
Thanks to Rob Mueller.

*) Feature: request body filters API now permits buffering of the data

being processed.

*) Bugfix: backend SSL connections in the stream module might hang after

an SSL handshake.

*) Bugfix: the security level, which is available in OpenSSL 1.1.0 or

newer, did not affect loading of the server certificates when set
with "@SECLEVEL=N" in the "ssl_ciphers" directive.

*) Bugfix: SSL connections with gRPC backends might hang if select,

poll, or /dev/poll methods were used.

*) Bugfix: when using HTTP/2 client request body was always written to

disk if the "Content-Length" header line was not present in the
request.

</Changelog>