Fix generation of wslua taps in out-of-source-tree builds when the source tree
is a source tarball (rather than git):

Don't put the $(srcdir) path (from when the source tarball was made) into the
C file: that file isn't regenerated when ./configure is run.  (This is a
correction to 0996730b91fddbf8aa7c61730a50da28ea1ab6a0).

Also change a few dependency paths so they'll work in out-of-source-tree builds.

Change-Id: I416f2d3611fb61659b9a7f7285e5f54a354fbe7d
Reviewed-on: https://code.wireshark.org/review/3554
Petri-Dish: Jeff Morriss <jeff.morriss.ws@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>