constify get_bookmark and goto_bookmark

constify get_bookmark and goto_bookmark

This makes arguments to to_get_bookmark and to_goto_bookmark const and
fixes the fallout.  Tested by rebuilding.  The only thing of note is
the new split between cmd_record_goto and record_goto -- basically
separating the CLI function from a new internal API, to allow const
propagation.

2014-06-26  Tom Tromey  <tromey@redhat.com>

	* record-full.c (record_full_get_bookmark): Make "args" const.
	(record_full_goto_bookmark): Make "raw_bookmark" const.
	* record.c (record_goto): New function.
	(cmd_record_goto): Use it.  Now static.
	* record.h (record_goto): Declare.
	(cmd_record_goto): Remove declaration.
	* target-delegates.c: Rebuild.
	* target.h (struct target_ops) <to_get_bookmark,
	to_goto_bookmark>: Make parameter const.