Throwing expected message if current subscription not set
Fixed failing unit test, made it consistent with rest of error messages. Removed now redundant null check
Merge pull request #1956 from christav/throw-on-no-subscription

Throwing expected message if current subscription not set
Management libraries update
Merge pull request #1960 from christav/fri-lunch-push

Management libraries update
Merge branch 'dev' of https://github.com/WindowsAzure/azure-sdk-tools into azurert-sm-integration
To fix Set/Get-AzureVNetConfig, Get-AzureVMImage, and PersistentVMRole issues.