* pt.c (type_unification_real): Fix handling of DEDUCE_CONV
	with no deducible template parameters.
	* call.c (rejection_reason_code): Add rr_template_conversion.
	(print_z_candidate): Handle it.
	(template_conversion_rejection): New.
	(build_user_type_conversion_1): Use it.

From-SVN: r178791