Vhd: Set-TargetResource uses try catch mechanism as logic to adjust or create a VHD

[bgelens]

Details of the scenario you tried and the problem that is occurring:
The logic is flawed as any terminating exception in the try block would result in a call to New-VHD which is not desired. This logic needs to be changed. See #77 for comments.

The DSC configuration that is using the resource (as detailed as possible):
NA

Version of the Operating System and PowerShell the DSC Target Node is running:
NA

Version of the DSC module you're using, or 'dev' if you're using current dev branch:
dev