Python API: Python translation for NodeNotReachableException

[redlicha]

Addresses #349

Before:

In [9]: client.list_volumes("node_1")
Out[9]: []

In [10]: !fusermount -u /tmp/RemoteTest/remote/mnt

In [11]: client.list_volumes("node_1")
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-11-1396f3ceb850> in <module>()
----> 1 client.list_volumes("node_1")

RuntimeError: failed to send XMLRPC request volumesList

After:

In [4]: client.list_volumes("node_1")
Out[4]: []

In [5]: !fusermount -u /tmp/RemoteTest/remote/mnt

In [6]: client.list_volumes("node_1")
---------------------------------------------------------------------------
NodeNotReachableException                 Traceback (most recent call last)
<ipython-input-6-1396f3ceb850> in <module>()
----> 1 client.list_volumes("node_1")

NodeNotReachableException: failed to send XMLRPC request volumesList

CC @kvanhijf , @JeffreyDevloo : is that sufficient for the fwk's purposes (keeping in mind that ClusterNotReachableException could also be raised in other cases)?

[JeffreyDevloo]

Could you provide us the path to import this exception from?

[redlicha]

@JeffreyDevloo : it's under volumedriver.storagerouter.storagerouterclient.