It is not possible to specify a depth larger than 1 with the tag
checkout that is performed. Move the depth increase to where it's
actually needed.

Issue: RELENG-4973
Signed-off-by: Andrew Grimberg <agrimberg@linuxfoundation.org>
Change-Id: I394c2359f8d8e8fec83bf5b39a9282222a9c2ad5