The commands are managed as entry-points so remove
ununecessary shebangs. Also lib/re2util.py does not
require a shebang as well.
zuul_return.py does not have a main and is not supposed
to be run directly.
Ununecessary shebangs for non executable script causes
rpmlint issues.
Change-Id: I6015daaa0fe35b6935fcbffca1907c01c9a26134