repozo: do not close file in concat function

But let the caller opening the file closing it

src/ZODB/scripts/repozo.py

@@ -360,8 +360,6 @@ def concat(files, ofp=None):
             ifp = open(f, 'rb')
         bytesread += dofile(func, ifp)
         ifp.close()
-    if ofp:
-        ofp.close()
     return bytesread, sum.hexdigest()
 
 

src/ZODB/scripts/tests/test_repozo.py

@@ -414,7 +414,7 @@ class Test_concat(OptionsTestBase, unittest.TestCase):
         ofp = Faux()
         bytes, sum = self._callFUT(files, ofp)
         self.assertEqual(ofp._written, [x.encode() for x in 'ABC'])
-        self.assertTrue(ofp._closed)
+        self.assertFalse(ofp._closed)
 
 _marker = object()
 class Test_gen_filename(OptionsTestBase, unittest.TestCase):