build: make fs_config_generator.py python2 explicitly
Test: run script in Fedora 31 with (default) python3 interpreter.
```
$ env python --version
Python 3.7.9
```
Change-Id: Ib4e68c5df54b092380e9fca473cd0dbbc0c18db7
diff --git a/tools/fs_config/fs_config_generator.py b/tools/fs_config/fs_config_generator.py
index 940a398..098fde6 100755
--- a/tools/fs_config/fs_config_generator.py
+++ b/tools/fs_config/fs_config_generator.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
"""Generates config files for Android file system properties.
This script is used for generating configuration files for configuring