Remove outdated comment

src/borg/__init__.py

@@ -1,7 +1,5 @@
 from packaging.version import parse as parse_version
 
-# IMPORTANT keep imports from borg here to a minimum because our testsuite depends on
-# being able to import borg.constants and then monkey patching borg.constants.PBKDF2_ITERATIONS
 from ._version import version as __version__