[Ada] Minor fix for imported C++ constructors

[Ada] Minor fix for imported C++ constructors

C++ constructors are imported as functions and then internally rewritten into
procedures taking the "this" pointer as first parameter.  Now this parameter is
not of an access type but of the type directly, so it must be In/Out and not
just In.

2018-07-17  Eric Botcazou  <ebotcazou@adacore.com>

gcc/ada/

	* exp_disp.adb (Gen_Parameters_Profile): Make the _Init parameter an
	In/Out parameter.
	(Set_CPP_Constructors): Adjust comment accordingly.

From-SVN: r262790