scripts: Explicit usage of Python 3 (scripts with __main__)

Use the program search path to find the Python 3 interpreter.

Patch created mechanically by running:

  $ sed -i "s,^#\!/usr/bin/\(env\ \)\?python$,#\!/usr/bin/env python3," \
       $(git grep -l 'if __name__.*__main__')
Reported-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Suggested-by: NDaniel P. Berrangé <berrange@redhat.com>
Suggested-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Acked-by: NStefan Hajnoczi <stefanha@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200130163232.10446-6-philmd@redhat.com>
Signed-off-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>

scripts/analyse-locks-simpletrace.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 #
 # Analyse lock events and compute statistics

scripts/decodetree.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copyright (c) 2018 Linaro Limited
 #
 # This library is free software; you can redistribute it and/or

scripts/device-crash-test

-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 #  Copyright (c) 2017 Red Hat Inc
 #

scripts/kvm/kvm_flightrecorder

-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # KVM Flight Recorder - ring buffer tracing script
 #

scripts/qapi-gen.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 # QAPI generator
 #
 # This work is licensed under the terms of the GNU GPL, version 2 or later.

scripts/qmp/qemu-ga-client

-#!/usr/bin/python
+#!/usr/bin/env python3
 
 # QEMU Guest Agent Client
 #

scripts/qmp/qmp

-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # QMP command line tool
 #

scripts/qmp/qmp-shell

-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Low-level QEMU shell on top of QMP.
 #

scripts/qmp/qom-fuse

-#!/usr/bin/python
+#!/usr/bin/env python3
 ##
 # QEMU Object Model test tools
 #

scripts/render_block_graph.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Render Qemu Block Graph
 #

scripts/replay-dump.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 #
 # Dump the contents of a recorded execution stream

scripts/simpletrace.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Pretty-printer for simple trace backend binary trace files
 #

scripts/tracetool.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 """

scripts/vmstate-static-checker.py

-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Compares vmstate information stored in JSON format, obtained from
 # the -dump-vmstate QEMU command.