GetRegistration and GetService methods lack null check

[dotnetjunkie]

Some methods on the public API of Container lack a proper null check when the supplied Type (serviceType) is a null reference. Those methods are:

• GetRegistration(Type serviceType, bool throwOnFailure)
• IServiceProvider.GetService(Type serviceType)

Those methods will eventually fail with a NullReferenceException, but they will do so with an exception mentioning the key argument, as Type is supplied to the dictionary's TryGetValue method.

Better solution is to check for null instead.

[dotnetjunkie]

bug-695 branch created.