In order to avoid race condition introduced in 9dce1e4 the
index_reader should be closed prior to it's destruction.
This only exposes 4.4 and earlier releases to this specific race.
However, it is always a good idea to first close the index reader
and only then destroy it since it is most likely to be assumed by
all developers that will change the reader index in the future.
Ref #9704 (because on 4.4 and earlier releases are vulnerable).
Signed-off-by: Eliran Sinvani <eliransin@scylladb.com>
Fixes#9704
(cherry picked from commit ddd7248b3b)
Closes#9717
5375b8f1a1