edge: nextcloud upload tests flaky

[butonic]

in https://drone.cernbox.cern.ch/cs3org/reva/8432/6/3

------------------------------
• [FAILED] [2.188 seconds]
storage providers
/drone/src/tests/integration/grpc/storageprovider_test.go:79
  nextcloud
  /drone/src/tests/integration/grpc/storageprovider_test.go:655
    with a home and a subdirectory
    /drone/src/tests/integration/grpc/storageprovider_test.go:665
      [It] returns upload URLs for simple and tus
      /drone/src/tests/integration/grpc/storageprovider_test.go:360

  Expected
      <rpcv1beta1.Code>: 15
  to equal
      <rpcv1beta1.Code>: 1
  In [It] at: /drone/src/tests/integration/grpc/storageprovider_test.go:364
------------------------------

[butonic]

was actually not flaky in #3148.

Protip: when runnig the integration tests locally eg. with ginkgo --until-it-fails tests/integration/grpc run a make clean build or an old binary might be used to run the tests.