t7112: remove mention of KNOWN_FAILURE_SUBMODULE_RECURSIVE_NESTED

The known failure mode KNOWN_FAILURE_SUBMODULE_RECURSIVE_NESTED was
removed from lib-submodule-update.sh in 218c883 (submodule: properly
recurse for read-tree and checkout, 2017-05-02) but at that time this
change was not ported over to topic sb/reset-recurse-submodules, such
that when this topic was merged in 5f074ca (Merge branch
'sb/reset-recurse-submodules', 2017-05-29), t7112-reset-submodules.sh
kept a mention of this removed failure mode.

Remove it now, as it does not mean anything anymore.

Signed-off-by: Philippe Blain <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: phil-blain

t/t7112-reset-submodule.sh

@@ -5,7 +5,6 @@ test_description='reset can handle submodules'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-submodule-update.sh
 
-KNOWN_FAILURE_SUBMODULE_RECURSIVE_NESTED=1
 KNOWN_FAILURE_DIRECTORY_SUBMODULE_CONFLICTS=1
 KNOWN_FAILURE_SUBMODULE_OVERWRITE_IGNORED_UNTRACKED=1