Change pre-upload hook check order for non python upload

It's currently not possible to run the pre-upload hook without having
to source the build/envsetup.sh.
With this change it will be allowed as long as there is no python files
modified.

Test: Upload this change (it's a python file)
Change-Id: I0a27c777b0a0aa58d48e42650063f62cba0a4027