t7411: be nicer to future tests and really clean things up

Tests 5 and 7 in t/t7411-submodule-config.sh add two commits with
invalid lines in .gitmodules but then only the second commit is removed.

This may affect future subsequent tests if they assume that the
.gitmodules file has no errors.

Remove both the commits as soon as they are not needed anymore.

Signed-off-by: Antonio Ospite <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ao2

t/t7411-submodule-config.sh

@@ -83,6 +83,8 @@ Submodule name: 'submodule' for path 'submodule'
 EOF
 
 test_expect_success 'error in history of one submodule config lets continue, stderr message contains blob ref' '
+	ORIG=$(git -C super rev-parse HEAD) &&
+	test_when_finished "git -C super reset --hard $ORIG" &&
 	(cd super &&
 		cp .gitmodules .gitmodules.bak &&
 		echo "	value = \"" >>.gitmodules &&
@@ -115,6 +117,8 @@ test_expect_success 'using different treeishs works' '
 '
 
 test_expect_success 'error in history in fetchrecursesubmodule lets continue' '
+	ORIG=$(git -C super rev-parse HEAD) &&
+	test_when_finished "git -C super reset --hard $ORIG" &&
 	(cd super &&
 		git config -f .gitmodules \
 			submodule.submodule.fetchrecursesubmodules blabla &&
@@ -126,8 +130,7 @@ test_expect_success 'error in history in fetchrecursesubmodule lets continue' '
 			HEAD b \
 			HEAD submodule \
 				>actual &&
-		test_cmp expect_error actual  &&
-		git reset --hard HEAD^
+		test_cmp expect_error actual
 	)
 '