python-dsl warnings around imp
python-dsl warnings around imp

Summary:
I run with PYTHONWARNINGS=once in my environment at all times.

imp is deprecated in python3 so there is a warning raised every time you import it.

imp.new_module(name) and types.ModuleType(name) are identical and the types one works in py2 if that is still a concern

```
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/tools/make_par/integration_tests/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/python/wheel/six/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/python/wheel/setuptools/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/tools/build/buck/wrappers/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/fbvscode/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/python/wheel/typing/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/tools/build/sanitizers/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/python/wheel/future/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/third-party-buck/platform009/tools/rocm/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
WARNING: Output when parsing /data/users/fried/fbsource/fbcode/tools/build/TARGETS:
| /data/users/fried/fbsource/fbcode/buck-out/tmp/resources/d0632ffbde0f6602b549f6a9756284f8/buck_server/buck_parser/module_whitelist.py:18: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
```

Reviewed By: thatch

fbshipit-source-id: 863dbba50294193932c2e7ff3b42d4ab582a8b6e

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