Minor updates to 00 Connection Plugin for vCenter.ps1, 01 General Information.ps1, and 20 Cluster\17 DRS Migrations.ps1

In "01 General Information.ps1" the change 1.2 that had $MigrationQuery2 not always created as an efficiency broke other areas that expected the variable to exist.  Specifically "00 Initialize\01 General Information.ps1" and "20 Cluster\17 DRS Migrations.ps1".  On line 45 added and if statement to handle that.

In "00 Connection Plugin for vCenter.ps1" the test on line 110 if the vCenter was an appliance left $VCSA nonexistent in most case.  I added [ else { $VCSA = $false } ] to take care of it.