fix(linstor): don't raise if volume cannot be deleted properly (#114)

In the case of a DRBD resource deletion issue via the LINSTOR API,
a wrong exception was thrown in the `VDI.delete` code instead of
simply logging and properly terminating the command.

Trace before correction:
```
Nov 26 08:19:58 xcp-node-1 SM: [1055074] Failed to remove the volume (maybe is leaf coalescing) for 389e891c-2150-4caa-b201-073dedb8b886 err: Cannot destroy volume `389e891c-2150-4caa-b201-073dedb8b886`: Could not destroy resource `xcp-
volume-9ef5f4a1-f101-4f34-8029-f2ad698decdd` from SR `xcp-sr-linstor_group_thin_device`: (Node: 'xcp-nodo-1') Failed to delete lvm volume
Nov 26 08:19:58 xcp-node-1 SM: [1055074] Raising exception [80, Failed to mark VDI hidden [opterr=Cannot destroy volume `389e891c-2150-4caa-b201-073dedb8b886`: Could not destroy resource `xcp-volume-9ef5f4a1-f101-4f34-8029-f2ad698decdd`
from SR `xcp-sr-linstor_group_thin_device`: (Node: 'xcp-nodo-1') Failed to delete lvm volume]]
Nov 26 08:19:58 xcp-node-1 SM: [1055074] lock: released /var/lock/sm/33dcb0ef-e089-4b6b-ab79-3d337045528e/sr
Nov 26 08:19:58 xcp-node-1 SM: [1150284] lock: acquired /var/lock/sm/33dcb0ef-e089-4b6b-ab79-3d337045528e/sr
Nov 26 08:19:58 xcp-node-1 SM: [1055074] ***** generic exception: vdi_delete: EXCEPTION <class 'xs_errors.SROSError'>, Failed to mark VDI hidden [opterr=Cannot destroy volume `389e891c-2150-4caa-b201-073dedb8b886`: Could not destroy res
ource `xcp-volume-9ef5f4a1-f101-4f34-8029-f2ad698decdd` from SR `xcp-sr-linstor_group_thin_device`: (Node: 'xcp-nodo-1') Failed to delete lvm volume]
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/SRCommand.py", line 113, in run
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     return self._run_locked(sr)
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/SRCommand.py", line 163, in _run_locked
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     rv = self._run(sr, target)
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/SRCommand.py", line 254, in _run
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     return target.delete(self.params['sr_uuid'], self.vdi_uuid)
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/LinstorSR", line 1775, in delete
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     raise xs_errors.XenError('VDIDelete', opterr=str(e))
Nov 26 08:19:58 xcp-node-1 SM: [1055074]
Nov 26 08:19:58 xcp-node-1 SM: [1055074] ***** LINSTOR resources on XCP-ng: EXCEPTION <class 'xs_errors.SROSError'>, Failed to mark VDI hidden [opterr=Cannot destroy volume `389e891c-2150-4caa-b201-073dedb8b886`: Could not destroy resou
rce `xcp-volume-9ef5f4a1-f101-4f34-8029-f2ad698decdd` from SR `xcp-sr-linstor_group_thin_device`: (Node: 'xcp-nodo-1') Failed to delete lvm volume]
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/SRCommand.py", line 392, in run
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     ret = cmd.run(sr)
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/SRCommand.py", line 113, in run
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     return self._run_locked(sr)
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/SRCommand.py", line 163, in _run_locked
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     rv = self._run(sr, target)
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/SRCommand.py", line 254, in _run
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     return target.delete(self.params['sr_uuid'], self.vdi_uuid)
Nov 26 08:19:58 xcp-node-1 SM: [1055074]   File "/opt/xensource/sm/LinstorSR", line 1775, in delete
Nov 26 08:19:58 xcp-node-1 SM: [1055074]     raise xs_errors.XenError('VDIDelete', opterr=str(e))
Nov 26 08:19:58 xcp-node-1 SM: [1055074]
```

Signed-off-by: Ronan Abhamon <ronan.abhamon@vates.tech>

Author: Wescoeur

drivers/LinstorSR.py

@@ -1772,7 +1772,7 @@ def delete(self, sr_uuid, vdi_uuid, data_only=False) -> None:
             )
 
             try:
-                raise xs_errors.XenError('VDIDelete', opterr=str(e))
+                raise e
             except LinstorVolumeManagerError as e:
                 if e.code != LinstorVolumeManagerError.ERR_VOLUME_DESTROY:
                     raise xs_errors.XenError('VDIDelete', opterr=str(e))