Remove hashbang from non-script python files

Many python files had a hashbang and the executable bit set though
they were not intended to be run a standalone script. That makes
determining which python files are actually scripts very difficult.
A future patch will update the hashbang in real python scripts so they
use $IMPALA_HOME/bin/impala-python.

Change-Id: I04eafdc73201feefe65b85817a00474e182ec2ba
Reviewed-on: http://gerrit.cloudera.org:8080/599
Reviewed-by: Casey Ching <casey@cloudera.com>
Reviewed-by: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Tested-by: Internal Jenkins

tests/query_test/test_partitioning.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 # Copyright (c) 2012 Cloudera, Inc. All rights reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");