Fix Unpatch default parameter

[Windows10CE]

Unpatch eventually calls into Patch.Remove, where the logic checks for "*" as the "remove all" wildcard, not null, which is the current default of Unpatch.

[pardeike]

Is this a breaking change (like discussed in http://www.thebillwagner.com/blog/Item/2010-08-23-DegreesofBreakingChangesOptionalParametersinC40) ?

[Windows10CE]

That article would count this change as a breaking one, yes, because the default behavior will change from doing nothing to unpatching all patches on a method. As I wouldn't expect a default optional parameter to have a method do nothing, the new default is likely what callers expected to happen.

So, there are two scenarios after a recompile:

1. Callers now get the expected behavior and everything works fine (not changing this here would've required a bugfix at the caller level)
2. Callers get expected behavior, but their code breaks as a result. However, this happening is basically a "I was relying on that broken code!".

Whether or not you consider it a breaking change depends on if you consider a bugfix that changes something to the expected behavior when people could've been relying (on accident) on the broken behavior to be a breaking change