rebase tests: camel-case rebase.rescheduleFailedExec consistently

Fix a test added in 906b639 (rebase --am: ignore
rebase.rescheduleFailedExec, 2019-07-01) to camel-case the
configuration variable. This doesn't change the behavior of the test,
it's merely to help its human readers.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

t/t3418-rebase-continue.sh

@@ -282,8 +282,8 @@ test_expect_success '--reschedule-failed-exec' '
 	test_i18ngrep "has been rescheduled" err
 '
 
-test_expect_success 'rebase.reschedulefailedexec only affects `rebase -i`' '
-	test_config rebase.reschedulefailedexec true &&
+test_expect_success 'rebase.rescheduleFailedExec only affects `rebase -i`' '
+	test_config rebase.rescheduleFailedExec true &&
 	test_must_fail git rebase -x false HEAD^ &&
 	grep "^exec false" .git/rebase-merge/git-rebase-todo &&
 	git rebase --abort &&