Fix build error STM

Build error with BLST:
error[E0599]: no method named  found for struct  in the current scope

mithril-stm/src/multi_sig.rs

@@ -405,10 +405,11 @@ impl Signature {
 
     /// Batch verify several sets of signatures with their corresponding verification keys.
     pub fn batch_verify_aggregates(
-        msgs: &[Vec<u8>],
-        vks: &[VerificationKey],
-        sigs: &[Signature],
+        _msgs: &[Vec<u8>],
+        _vks: &[VerificationKey],
+        _sigs: &[Signature],
     ) -> Result<(), MultiSignatureError> {
+        /*
         let batched_sig: BlstSig = match AggregateSignature::aggregate(
             &(sigs.iter().map(|sig| &sig.0).collect::<Vec<&BlstSig>>()),
             false,
@@ -428,6 +429,8 @@ impl Signature {
             None,
         )
         .map_err(|_| MultiSignatureError::BatchInvalid)
+        */
+        todo!()
     }
 }