No need to remove initiator if FC is used

[PavelKolobaev]

Version: 2.5.RC4
On this code
https://github.com/Huawei/OpenStack_Driver/blob/2.5.4/Cinder/Xena/huawei_flow.py#L1751-L1753

When used FC we found logs and not use zoning_mode in cinder

URL: https://x.x.x.x:8088/deviceManager/rest/2102352QCL9WKC800025/iscsi_initiator/iqn.1993-08.org.debian:01:95adb9ba6656
Method: put
Data: {'USECHAP': 'false', 'MULTIPATHTYPE': '0'}

Response: {'data': {}, 'error': {'code': 1077948996, 'description': 'The specified object is unavailable.', 'suggestion': 'Enter a valid object.'}}

Update initiator iqn.1993-08.org.debian:01:95adb9ba6656 chap error.
result: {'data': {}, 'error': {'code': 1077948996, 'description': 'The specified object is unavailable.', 'suggestion': 'Enter a valid object.'}}.

Terminate volume connection failed: Bad or unexpected response from the storage volume backend API: Update initiator iqn.1993-08.org.debian:01:95adb9ba6656 chap error.
result: {'data': {}, 'error': {'code': 1077948996, 'description': 'The specified object is unavailable.', 'suggestion': 'Enter a valid object.'}}.

Version: 2.5.RC3 - work fine

How to reproduce:
Create and attach a disk that will be the only one on the host.
Remove disk, an error will appear.

<config>
<Storage>
  <Product>Dorado</Product>
  <Protocol>FC</Protocol>
  <UserName>cccccc</UserName>
  <UserPassword>cccc</UserPassword>
  <RestURL>https://x.x.x.x:8088/deviceManager/rest/;https://x.x.x.c:8088/deviceManager/rest/</RestURL>
</Storage>
<LUN>
  <LUNType>Thin</LUNType>
  <WriteType>1</WriteType>
   <StoragePool>SP-main</StoragePool>
</LUN>
<FC>
  <Initiator SPECIALMODETYPE="0" FAILOVERMODE="3" ALUA="1" PATHTYPE="0" HostName="*" Name="*" MULTIPATHTYPE="1"/>
  <MinOnlineFCInitiator>0</MinOnlineFCInitiator>
</FC>
</config>