nginx-devel: updated to 1.15.5

Changes with nginx 1.15.5:

*) Bugfix: a segmentation fault might occur in a worker process when
  using OpenSSL 1.1.0h or newer; the bug had appeared in 1.15.4.

*) Bugfix: of minor potential bugs.

Changes with nginx 1.15.4:

*) Feature: now the "ssl_early_data" directive can be used with OpenSSL.

*) Bugfix: in the ngx_http_uwsgi_module.
  Thanks to Chris Caputo.

*) Bugfix: connections with some gRPC backends might not be cached when
  using the "keepalive" directive.

*) Bugfix: a socket leak might occur when using the "error_page"
  directive to redirect early request processing errors, notably errors
  with code 400.

*) Bugfix: the "return" directive did not change the response code when
  returning errors if the request was redirected by the "error_page"
  directive.

*) Bugfix: standard error pages and responses of the
  ngx_http_autoindex_module module used the "bgcolor" attribute, and
  might be displayed incorrectly when using custom color settings in
  browsers.
  Thanks to Nova DasSarma.

*) Change: the logging level of the "no suitable key share" and "no
  suitable signature algorithm" SSL errors has been lowered from "crit"
  to "info".

(adam)