Fix another (valid) complaint from the mac buildbot

What mystical new compiler upgrade is this?

Change-Id: I89b3bfb53b9a19bbfb1cc8339d38cdc4a4652c62
Reviewed-on: https://code.wireshark.org/review/3347
Reviewed-by: Evan Huus <eapache@gmail.com>
Revert "Make Lua taps work in out-of-source-tree builds."

Breaks on windows...

This reverts commit 6b11cd97f2153bb015ade6efd05929999de85457.

Change-Id: I1caf5500da993d7988e09fc0758950469f8252cf
Reviewed-on: https://code.wireshark.org/review/3346
Reviewed-by: Evan Huus <eapache@gmail.com>