(closes issue #13558)

Reported by: mnicholson

Considering that the example extensions.lua used nothing but ["12345"] notation,
and that the resulting error message: 

[Sep 24 17:01:16] ERROR[12393]: pbx_lua.c:1204 exec: Error executing lua extension: attempt to call a nil value

is not very informative as to the nature of the problem, I think this bug
fix is a big win!





git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@144482 65c4cc65-6c06-0410-ace0-fbb531ad65f3