Pod fails if PVC already exists

[lvarin]

If the PVC already exists, the pods fails ungraciously:

$ oc logs task-0675c153-zvsw9                  
Traceback (most recent call last):
  File "/usr/bin/taskmaster.py", line 301, in <module>
    main(sys.argv)
  File "/usr/bin/taskmaster.py", line 262, in main
    run_task(data, args.filer_version)
  File "/usr/bin/taskmaster.py", line 139, in run_task
    pvc = init_pvc(data, filer)
  File "/usr/bin/taskmaster.py", line 107, in init_pvc
    pvc.create()
  File "/usr/bin/pvc.py", line 37, in create
    return self.cv1.create_namespaced_persistent_volume_claim(self.namespace, self.spec)
  File "/usr/lib/python2.7/site-packages/kubernetes/client/apis/core_v1_api.py", line 5950, in create_namespaced_persistent_volume_claim
    (data) = self.create_namespaced_persistent_volume_claim_with_http_info(namespace, body, **kwargs)
  File "/usr/lib/python2.7/site-packages/kubernetes/client/apis/core_v1_api.py", line 6035, in create_namespaced_persistent_volume_claim_with_http_info
    collection_formats=collection_formats)
  File "/usr/lib/python2.7/site-packages/kubernetes/client/api_client.py", line 321, in call_api
    _return_http_data_only, collection_formats, _preload_content, _request_timeout)
  File "/usr/lib/python2.7/site-packages/kubernetes/client/api_client.py", line 155, in __call_api
    _request_timeout=_request_timeout)
  File "/usr/lib/python2.7/site-packages/kubernetes/client/api_client.py", line 364, in request
    body=body)
  File "/usr/lib/python2.7/site-packages/kubernetes/client/rest.py", line 266, in POST
    body=body)
  File "/usr/lib/python2.7/site-packages/kubernetes/client/rest.py", line 222, in request
    raise ApiException(http_resp=r)
kubernetes.client.rest.ApiException: (409)
Reason: Conflict
HTTP response headers: HTTPHeaderDict({'Date': 'Wed, 13 May 2020 10:04:40 GMT', 'Content-Length': '248', 'Content-Type': 'application/json', 'Cache-Control': 'no-store'})
HTTP response body: {"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"persistentvolumeclaims \"task-0675c153-pvc\" already exists","reason":"AlreadyExists","details":{"name":"task-0675c153-pvc","kind":"persistentvolumeclaims"},"code":409}