web2go: copy tangled file to destination
This CL removes the use of os.Rename to produce the resulting TANGLEd file to its final destination, as the $TMP directory may be on a different device than the resulting destination. This fixes this kind of error:
rename tex.p /tmp/web2go-test-2439105947/tex.p: invalid cross-device link
Signed-off-by: Sebastien Binet binet@cern.ch