os-apply-config: fix python shebang in %prep instead of %check
os-apply-config: fix python shebang in %prep instead of %check

By doing this, the script.conf file that ends up in the package has
the correct shebang. Failure to do so causes a build failure in
CentOS 8.

Change-Id: I1c5dae6a706407dc65dc81386e799aca4a29edb0

openstack/rpm-packaging,openstack/rpm-packaging