Issue #7732: Fix a crash on importing a module if a directory has the same name

than a Python module (e.g. "__init__.py"): don't close the file twice.

PyFile_FromFile() does also close the file if PyString_FromString() failed. It
did already close the file on fill_file_fields() error (e.g. if the file is a
directory).

Lib/test/test_import.py

@@ -265,6 +265,14 @@ class ImportTests(unittest.TestCase):
             """))
         script_helper.assert_python_ok(testfn)
 
+    def test_bug7732(self):
+        source = TESTFN + '.py'
+        os.mkdir(source)
+        try:
+            self.assertRaises(IOError, imp.find_module, TESTFN, ["."])
+        finally:
+            os.rmdir(source)
+
 
 class PycRewritingTests(unittest.TestCase):
     # Test that the `co_filename` attribute on code objects always points