Address review comments

setuptools/command/sdist.py

@@ -6,7 +6,6 @@ import io
 import contextlib
 
 from setuptools.extern import six
-from setuptools.extern.six.moves import configparser
 
 from .py36compat import sdist_add_defaults
 
@@ -206,11 +205,12 @@ class sdist(sdist_add_defaults, orig.sdist):
         """
 
         opts = self.distribution.get_option_dict('metadata')
-        try:
-            # ignore the source of the value
-            _, license_file = opts.get('license_file')
-        except TypeError:
-            log.debug("'license_file' attribute is not defined")
+
+        # ignore the source of the value
+        _, license_file = opts.get('license_file', (None, None))
+
+        if license_file is None:
+            log.debug("'license_file' option was not specified")
             return
 
         if not os.path.exists(license_file):

setuptools/tests/test_egg_info.py

@@ -529,8 +529,10 @@ class TestEggInfo:
             env=environ,
         )
         egg_info_dir = os.path.join('.', 'foo.egg-info')
+
         with open(os.path.join(egg_info_dir, 'SOURCES.txt')) as sources_file:
             sources_text = sources_file.read()
+
         if license_in_sources:
             assert 'LICENSE' in sources_text
         else: