I explained this in commit message.
The property name is 'target_path', so when we get XMLElementText of this propery, function name get_target_path() will conflict with XML accessors inside function, which will lead to an exception:
```
14:14:54 ERROR| Traceback (most recent call last):
14:14:54 ERROR|   File "/home/ydu/Work/run/virt-test/virttest/standalone_test.py", line 196, in run_once
14:14:54 ERROR|     run_func(self, params, env)
14:14:54 ERROR|   File "/home/ydu/Work/run/virt-test/libvirt/tests/src/virsh_cmd/pool/virsh_pool_edit.py", line 124, in run
14:14:54 ERROR|     target_path = pool_xml.PoolXML.get_target_path(name=pool)
14:14:54 ERROR|   File "/home/ydu/Work/run/virt-test/virttest/libvirt_xml/pool_xml.py", line 206, in get_target_path
14:14:54 ERROR|     return pool_xml.target_path
14:14:54 ERROR|   File "/home/ydu/Work/run/virt-test/virttest/propcan.py", line 223, in __getattr__
14:14:54 ERROR|     return self.__getitem__(key)
14:14:54 ERROR|   File "/home/ydu/Work/run/virt-test/virttest/propcan.py", line 183, in __getitem__
14:14:54 ERROR|     return accessor()
14:14:54 ERROR| TypeError: get_target_path() takes at least 1 argument (0 given)
```