Move gtk app to the correct location. Thanks obnox!

Guenther
(This used to be commit 740a2b080db56d504c4edd58bf41d72edb3d32ee)

diff --git a/source3/lib/netapi/examples/netdomjoin/netdomjoin-gui.c b/source3/lib/netapi/examples/netdomjoin-gui/netdomjoin-gui.c
similarity index 100%
rename from source3/lib/netapi/examples/netdomjoin/netdomjoin-gui.c
rename to source3/lib/netapi/examples/netdomjoin-gui/netdomjoin-gui.c