As discussed with @librehat in #1604, maintaining a separate set of systemd
files for RPM distributions will be convenient to build on Copr.
This patch will also change some lines in rpm/genrpm.sh to archive the
source code using `git archive` because the old logic doesn't respect
`.gitignore`.
it's not conflicted with shadowsocks-python now. users can install both python and libev
ports of shaowsocks now. but they should migrate their old configuration file from
/etc/shadowsocks/config.json to /etc/shadowsocks-libev/config.json
Note:
Debian/Ubuntu users may have to `sudo rm -f /etc/shadowsocks` before install
the new `shadowsocks-libev` package.
For library user, the pkg-config package is renamed to `shadowsocks-libev` but
the library name is still the `libshadowsocks` (use `-lshadowsocks` to link)