Added code to disable snapshot buttons for SCVMM VMs.

https://bugzilla.redhat.com/show_bug.cgi?id=1141174
https://bugzilla.redhat.com/show_bug.cgi?id=1141375

@dclarizio please review/test.
@jrafanie in the db i that have, vendor is set to unknown for SCVMM Vm, whereas type was set to VmMicrosoft which is why i have added a check to return false if VM type is VmMicrosoft. Probably @bronaghs can specify the case when vendor will be set to Microsoft.