mr_list: fix test latest MR
mr_list: fix test latest MR

There are some tests that relies on the last MR opened. One was created for
testing MR closing and reopening, which became the last. With that the
reference in mr_list_test should be changed.

Signed-off-by: Bruno Meneguele <82c7731bc2625bcbab88bc571aee6631ba3f66f3@redhat.com>

zaquestion/lab,zaquestion/lab