* [httperf] Fix Issue #43 - update config / build instructions.
* The installation steps given in current README fail. I had to follow steps given in the comments of a previous Issue to build it properly. I am including those steps in README, as they are pretty generic and should work for everyone.
* Fix segfault when connection is failed by using epoll(7).
* Teach to use epoll(7) on httperf(1).
* Use correct ifdefs for checking TLS 1.3
OBS-URL: https://build.opensuse.org/package/show/benchmark/httperf?expand=0&rev=17
