fixup! Fix the Allocation lifetime in File::open

Author: sosthene-nitrokey

src/fs.rs

@@ -627,7 +627,6 @@ pub struct File<'a, 'b, S: driver::Storage> {
     // We must store a raw pointer here since the FFI retains a copy of a pointer
     // to the field alloc.state, so we cannot assert unique mutable access.
     alloc: RefCell<*mut FileAllocation<S>>,
-    phantom: PhantomData<RefCell<&'b mut FileAllocation<S>>>,
     fs: &'b Filesystem<'a, S>,
 }
 
@@ -835,7 +834,6 @@ impl OpenOptions {
 
         let file = File {
             alloc: RefCell::new(alloc),
-            phantom: PhantomData,
             fs,
         };