MDEV-11690 Remove UNIV_HOTBACKUP

The InnoDB source code contains quite a few references to a closed-source
hot backup tool which was originally called InnoDB Hot Backup (ibbackup)
and later incorporated in MySQL Enterprise Backup.

The open source backup tool XtraBackup uses the full database for recovery.
So, the references to UNIV_HOTBACKUP are only cluttering the source code.

storage/innobase/include/btr0cur.h

@@ -60,7 +60,6 @@ struct btr_latch_leaves_t {
 	ulint		savepoints[3];
 };
 
-#ifndef UNIV_HOTBACKUP
 #include "que0types.h"
 #include "row0types.h"
 #include "ha0ha.h"
@@ -530,7 +529,6 @@ btr_cur_pessimistic_delete(
 	bool		rollback,/*!< in: performing rollback? */
 	mtr_t*		mtr)	/*!< in: mtr */
 	MY_ATTRIBUTE((nonnull));
-#endif /* !UNIV_HOTBACKUP */
 /***********************************************************//**
 Parses a redo log record of updating a record in-place.
 @return end of log record or NULL */
@@ -565,7 +563,6 @@ btr_cur_parse_del_mark_set_sec_rec(
 	byte*		end_ptr,/*!< in: buffer end */
 	page_t*		page,	/*!< in/out: page or NULL */
 	page_zip_des_t*	page_zip);/*!< in/out: compressed page, or NULL */
-#ifndef UNIV_HOTBACKUP
 
 /** Estimates the number of rows in a given index range.
 @param[in]	index	index
@@ -941,7 +938,6 @@ btr_rec_set_deleted_flag(
 	page_zip_des_t*	page_zip,/*!< in/out: compressed page (or NULL) */
 	ulint		flag);	/*!< in: nonzero if delete marked */
 
-
 /** If pessimistic delete fails because of lack of file space, there
 is still a good change of success a little later.  Try this many
 times. */
@@ -995,7 +991,6 @@ extern ulint	btr_cur_n_non_sea_old;
 srv_refresh_innodb_monitor_stats().  Referenced by
 srv_printf_innodb_monitor(). */
 extern ulint	btr_cur_n_sea_old;
-#endif /* !UNIV_HOTBACKUP */
 
 #ifdef UNIV_DEBUG
 /* Flag to limit optimistic insert records */