...when throwing an exception from implicitly noexcept ~GErrorWrapper.  So make
~GErrorWrapper noexcept(false) and see that no code executed while a
GErrorWrapper instance is active on the stack would throw an exception.  But the
design of GErrorWrapper, to throw an exception from a dtor, is very brittle and
should be fixed.

Change-Id: Ib04ff2b0497c160dc7ee44c3354fa9619285ec88