Fix Set-AzureRmSqlDatabaseBackupLongTermRetentionPolicy Cmdlet

[trgrie]

Description

This is a bug fix for Set-AzureRmSqlDatabaseBackupLongTermRetentionPolicy cmdlet so that the current flag in Get-AzureRmSqlDatabaseLongTermRetentionPolicy is properly set to true when using LTR V2.

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate change log has been updated
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • the changes have gone through a cmdlet design review
  • the cmdlet markdown files were generated using the platyPS module

[maddieclayton]

on demand here: https://azuresdkci.westus2.cloudapp.azure.com/view/PowerShell/job/powershell-demand/817/