decl.c (duplicate_decls): Always merge the old and new patterns for templates...

decl.c (duplicate_decls): Always merge the old and new patterns for templates...

	* decl.c (duplicate_decls): Always merge the old and new patterns
	for templates, regardless of whether or not the new one has
	DECL_INITIAL.  Don't throw away specializations.  Merge
	DECL_SAVED_TREE.
	* pt.c (tsubst_decl): Use the right pattern when calculating the
	complete args for a new template instance.
	(do_decl_instantiation): Fix typo in comment.
	(regenerate_decl_from_template): Deal with tricky friend template
	case.
	(instantiate_decl): Likewise.

From-SVN: r21876