This bug fix requires that Bug #58912 be fixed as well (bzr revision id
marko.makela@oracle.com-20101221093919-mcmmgd4zpse9567d). Otherwise,
another double BLOB free could occur when InnoDB would try to perform
an update-in-place as delete-and-insert-by-update-in-place.

row_upd_clust_rec_by_insert(): Do not disown the externally stored
columns from the old record (btr_cur_mark_extern_inherited_fields())
until after checking the foreign key constraints and successfully
inserting the updated record. If a lock wait timeout occurs between
the delete-marking of the old record and the insertion of the updated
record, mark the columns inherited before retrying the insert.
Distinguish the state UPD_NODE_INSERT_BLOB from
UPD_NODE_INSERT_CLUSTERED.

btr_cur_del_mark_set_clust_rec(): Replace the cursor with
block,rec,index,offsets so that the offsets need not be recalculated.
Assert that rec is on a clustered index leaf page.

btr_cur_disown_inherited_fields(): Renamed from
btr_cur_mark_extern_inherited_fields(). Use
upd_get_field_by_field_no(). Assert that there are externally stored
columns. Assert that a mini-transaction is passed. Remove the return
status. (The only caller, row_upd_clust_rec_by_insert(), will have
determined that some fields have changed ownership.)

btr_cur_mark_dtuple_inherited_extern(): Rename to
row_upd_clust_rec_by_insert_inherit_func() and declare as static. Add
the debug parameters rec, offsets. When rec is given, assert that the
off-page columns match those in the inesrt tuple and that the off-page
columns are owned by the record. Assert that the non-updated off-page
columns in the insert tuple are owned, and mark them inherited.

row_upd_clust_rec_by_insert_inherit(): A wrapper macro for
row_upd_clust_rec_by_insert_inherit_func().

row_undo_mod_upd_exist_sec(): Adjust a comment about
row_upd_clust_rec_by_insert().

rb:508 approved by Jimmy Yang