[fix] tests: Fix makeNewRelease when installed as a zipped egg

python ZipFile module does not support updating an entry in place, instead make
a new zip file and copy all entries.

src/zc/buildout/tests/test_all.py

@@ -3444,16 +3444,18 @@ def makeNewRelease(project, ws, dest, version='99.99'):
     eggname, oldver, pyver = egg_parse(dist.egg_name()).groups()
     dest = os.path.join(dest, "%s-%s-py%s.egg" % (eggname, version, pyver))
     if os.path.isfile(dist.location):
-        shutil.copy(dist.location, dest)
-        zip = zipfile.ZipFile(dest, 'a')
-        zip.writestr(
-            'EGG-INFO/PKG-INFO',
-            ((zip.read('EGG-INFO/PKG-INFO').decode('ISO-8859-1')
-              ).replace("Version: %s" % oldver,
-                        "Version: %s" % version)
+        with zipfile.ZipFile(dist.location, 'r') as old_zip:
+            with zipfile.ZipFile(dest, 'w') as new_zip:
+                for item in old_zip.infolist():
+                    data = old_zip.read(item.filename)
+                    if item.filename == 'EGG-INFO/PKG-INFO':
+                        data = data.decode(
+                            'ISO-8859-1'
+                          ).replace(
+                            "Version: %s" % oldver,
+                            "Version: %s" % version
                           ).encode('ISO-8859-1')
-            )
-        zip.close()
+                    new_zip.writestr(item, data)
     elif dist.location.endswith('site-packages'):
         os.mkdir(dest)
         shutil.copytree(