python: always use python3 in the shebang of programs using setools

setools 4.2.0 dropped support for Python 2. On systems where
/usr/bin/python is Python 2, several tools are now broken because of
this. Update the shebang of these tools to /usr/bin/python3.

For future reference, as semanage/seobject.py, sepolicy and sepolgen
import setools, every program that uses one of these modules need to be
run with Python 3. The following programs do not use any of these
modules so their shebangs have not been modified:

    dbus/selinux_server.py
    libsemanage/utils/semanage_migrate_store
    mcstrans/share/util/mlscolor-test
    mcstrans/share/util/mlstrans-test
    sandbox/start

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>

gui/polgengui.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python -Es
+#!/usr/bin/python3 -Es
 #
 # polgengui.py - GUI for SELinux Config tool in system-config-selinux
 #

gui/system-config-selinux.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python -Es
+#!/usr/bin/python3 -Es
 #
 # system-config-selinux.py - GUI for SELinux Config tool in system-config-selinux
 #

python/audit2allow/audit2allow

@@ -1,4 +1,4 @@
-#! /usr/bin/python -Es
+#!/usr/bin/python3 -Es
 # Authors: Karl MacMillan <kmacmillan@mentalrootkit.com>
 # Authors: Dan Walsh <dwalsh@redhat.com>
 #

python/audit2allow/sepolgen-ifgen

@@ -1,4 +1,4 @@
-#! /usr/bin/python -Es
+#!/usr/bin/python3 -Es
 #
 # Authors: Karl MacMillan <kmacmillan@mentalrootkit.com>
 #

python/chcat/chcat

@@ -1,4 +1,4 @@
-#! /usr/bin/python -Es
+#!/usr/bin/python3 -Es
 # Copyright (C) 2005 Red Hat
 # see file 'COPYING' for use and warranty information
 #

python/sepolicy/sepolicy.py

@@ -1,4 +1,4 @@
-#! /usr/bin/python -Es
+#!/usr/bin/python3 -Es
 # Copyright (C) 2012 Red Hat
 # AUTHOR: Dan Walsh <dwalsh@redhat.com>
 # see file 'COPYING' for use and warranty information

sandbox/sandbox

@@ -1,4 +1,4 @@
-#! /usr/bin/python -Es
+#!/usr/bin/python3 -Es
 # Authors: Dan Walsh <dwalsh@redhat.com>
 # Authors: Thomas Liu <tliu@fedoraproject.org>
 # Authors: Josh Cogliati