Add a vm snapshots check before reinstalling vm

[andrewbents]

If a VM has snapshot, reinstall action if not allowed (closes #1540)

[coveralls]

Pull Request Test Coverage Report for Build 1898

• 31 of 31 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 53.756%

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Totals
Change from base Build 1897:	0.1%
Covered Lines:	9789
Relevant Lines:	16182

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💛 - Coveralls

[bwsw]

@andrewbents please, fix PR conflict.