Remove invalid submodule Fixes #4274
diff --git a/tests/resources/rebase-submodule/my-submodule b/tests/resources/rebase-submodule/my-submodule
deleted file mode 160000
index efad0b1..0000000
--- a/tests/resources/rebase-submodule/my-submodule
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit efad0b11c47cb2f0220cbd6f5b0f93bb99064b00