go test list.Blobs undefined

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## This issue is a: (mark with an `x`)

- [x] bug report
- [ ] request for new sample
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)

## Steps to reproduce:
I cloned the repository and created a .env file:
AZURE_TENANT_ID=cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx6
AZURE_CLIENT_ID=6xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxc
AZURE_CLIENT_SECRET=Oxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx6
AZURE_SUBSCRIPTION_ID=5xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx1
AZURE_STORAGE_ACCOUNT_NAME=
AZURE_STORAGE_ACCOUNT_GROUP_NAME=
AZURE_RG_NAME=Pxxxxxxxxxxxl
AZURE_LOCATION=test

## Errors and log messages:
running go test gives me the following error:
# github.com/Azure-Samples/azure-sdk-for-go-samples/storage [github.com/Azure-Samples/azure-sdk-for-go-samples/storage.test]
./container_test.go:44:58: list.Blobs undefined (type *azblob.ListBlobsFlatSegmentResponse has no field or method Blobs)
FAIL github.com/Azure-Samples/azure-sdk-for-go-samples/storage [build failed]

## Expected behavior:
maybe the test should fail but the build should pass.

## OS and Go versions:
Ubuntu 19.10
go 1.1.2.17

## Further info:

Run go test in the storage package and inspect container_test.go around line 44, where ListBlobsFlatSegmentResponse.Blobs is referenced. Compare that usage with the available Azure SDK response type and confirm the package builds successfully; the issue is done when go test no longer fails at compilation.

Written by the indexing model from the issue text.