test: disable init_storage.test.py due to bug

Disable the init_storage.test.py test due to the bug #6966.
After a bug fix the test should be enabled again.

NO_DOC=testing stuff
NO_CHANGELOG=testing stuff
NO_TEST=testing stuff

(cherry picked from commit cab6822f)

test/replication-py/init_storage.skipcond

+# Disabled until bug tarantool/tarantool#6966 is resolved.
+self.skip = 1