repo 1.6.7.1

Perform copy file activity when creating a new work directory

Performance improvements in repo sync caused us to skip out of the
initial Sync_LocalHalf without ever running CopyFiles, so we didn't
create the top level Makefile in new clients whose manifest request
one with a <copyfile> element.

Now we run CopyFiles after the initial read-tree that populates
the project working directory.

Signed-off-by: Shawn O. Pearce <sop@google.com>