Remove unused throws exception on close

[ggivo]

AzureTokenAuthConfigBuilder.close method can not throw an exception.
Removing the throws clause no need to enforce exception handling.

[atakavci]

looks good, thanks

[atakavci]

on a second look, this is part of AutoClosable interface, so i think we should keep it.

[ggivo]

@atakavci
I think it should be removed. It is following the recommendations for implementing Autoclosable.
e.g if the implementation can not throw an exception remove it from the method signature

http://docs.oracle.com/javase/8/docs/api/java/lang/AutoCloseable.html#close--

While this interface method is declared to throw Exception, implementers are strongly encouraged to declare concrete implementations of the close method to throw more specific exceptions, or to throw no exception at all if the close operation cannot fail.

[atakavci]

LGTM