Make "set debug frame 1" output print <not saved> instead of <optimized out>.

"set debug frame 1" is printing "<optimized out>" for not saved
registers.  That's because the unwinders are returning optimized out
not_lval values instead of optimized out lval_register values.  "<not
saved>" is how val_print_optimized_out prints lval_register values.

  ...
  - { frame_unwind_register_value (frame=0,regnum=7(rsp),...) -> <optimized out> }
  + { frame_unwind_register_value (frame=0,regnum=7(rsp),...) -> <not saved> }
  ...

Tested on x86_64 Fedora 17.

2013-11-27  Pedro Alves  <palves@redhat.com>

	* frame-unwind.c (frame_unwind_got_optimized): Return
	an lval_register value instead of a not_lval value.

Author: palves

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2013-11-27  Pedro Alves  <palves@redhat.com>
+
+	* frame-unwind.c (frame_unwind_got_optimized): Return
+	an lval_register value instead of a not_lval value.
+
 2013-11-27  Andrew Burgess  <aburgess@broadcom.com>
 
 	* frame.c: Include "valprint.h".

gdb/frame-unwind.c

@@ -161,10 +161,12 @@ default_frame_unwind_stop_reason (struct frame_info *this_frame,
 struct value *
 frame_unwind_got_optimized (struct frame_info *frame, int regnum)
 {
-  struct gdbarch *gdbarch = frame_unwind_arch (frame);
-  struct type *reg_type = register_type (gdbarch, regnum);
+  struct value *val;
 
-  return allocate_optimized_out_value (reg_type);
+  val = value_of_register_lazy (frame, regnum);
+  set_value_lazy (val, 0);
+  set_value_optimized_out (val, 1);
+  return val;
 }
 
 /* Return a value which indicates that FRAME copied REGNUM into