Lua: Lua => Lua51

See [this](https://github.com/Homebrew/homebrew/pull/29236) PR for more
details. This is step 1 described in
[this](https://github.com/Homebrew/homebrew/pull/29236#issuecomment-5397
1789) comment.
Lua => Lua51

Fixes the test calling Lua without the version stopper.
Lua => Lua51

Cleans it up a bit.
Lua => Lua51

This is pretty much a test. I’m hoping by bumping the pkg-config I can
get the bot to automatically find the new lua library location. If that
doesn’t work might have to look at manually specifying where the new
lua libraries are for each affected formula, eek.
lighttpd: update 1.4.35_1 bottle.
lua51: update 5.1.5 bottle.
luarocks: add 2.1.2_1 bottle.
macvim: add 7.4-73_1 bottle.
metalua: add 0.5-rc2_1 bottle.
pdnsrec: add 3.6.0_1 bottle.
pkg-config: update 0.28_1 bottle.
radare2: add 0.9.7_1 bottle.
rrdtool: add 1.4.8_1 bottle.
tracebox: update 0.2_1 bottle.
uwsgi: update 2.0.6_1 bottle.
vim: add 7.4.335_1 bottle.
weechat: update 1.0_1 bottle.
wireshark: update 1.12.0_1 bottle.