This was really due to some stray decrements left over from an earlier
refactor; the newer code tracks the counts using RAII so the manual
decrements should not be needed any more.
To make the counters consistent when using lua connections, introduce
the same connection wrapping container over there, plus some glue
to make it possible to move the inner connection out of the wrapper
to destroy it when the connection is closed.
closes: #66
Wez Furlong
f40a7ac4e2