Remove unused variable from two tests

tests/threshold.rs

@@ -23,7 +23,6 @@ fn threshold_test() -> sigma_proofs::errors::Result<()> {
     let G4 = G::hash_from_bytes::<Sha512>(b"Generator G4");
     let G5 = G::hash_from_bytes::<Sha512>(b"Generator G5");
     let r = Scalar::random(&mut rng);
-    let y = Scalar::random(&mut rng);
 
     // Iterate over all combinations of 5 bits
     for true_pattern in 0u32..32 {

tests/threshold_pubscalars.rs

@@ -23,7 +23,6 @@ fn threshold_pubscalars_test() -> sigma_proofs::errors::Result<()> {
     let G4 = G::hash_from_bytes::<Sha512>(b"Generator G4");
     let G5 = G::hash_from_bytes::<Sha512>(b"Generator G5");
     let r = Scalar::random(&mut rng);
-    let y = Scalar::random(&mut rng);
 
     // Iterate over all combinations of 5 bits
     for true_pattern in 0u32..32 {