set-property without newVersion property doesn't give a useful error message

[smithkm]

If the set-property goal is executed but newVersion isn't set (in my case I had set new.version instead) the execution simply fails without any useful error message. With the -X flag the error is shown to be a NullPointerException which doesn't give any idea what the problem is, Giving a useful error that included the name of the missing parameter would make this kind of problem far easier to resolve.