Add new upstream Lua patches and rename all patches for consistency

Several new upstream patches against the latest version of Lua have
appeared on http://www.lua.org/bugs.html. This commit adds them to
Buildroot, and also renames the other patches to have a coherent patch
naming: lua-bugX, where X is the identifier of the bug as visible on
http://www.lua.org/bugs.html

. Note that bug 1 and 2 are not associated
with patches, which explains why the first patch is labeled lua-bug3.

Fixes bug #2365.

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>