remove remaining 0.30 conversion scaffolding

Author: apoelstra

src/hex.rs

@@ -231,36 +231,6 @@ impl io::Write for HexWriter {
     }
 }
 
-/*
-macro_rules! impl_from_bitcoin29_hex {
-    ($ty:ty) => {
-        impl FromHex for $ty {
-            fn from_byte_iter<I>(iter: I) -> Result<Self, Error>
-            where
-                I: Iterator<Item = Result<u8, Error>> + ExactSizeIterator + DoubleEndedIterator,
-            {
-                use bitcoin::hashes::hex::Error as Error29;
-
-                let iter = iter.map(|res| res.map_err(|err| match err {
-                    Error::InvalidChar(n) => Error29::InvalidChar(n),
-                    Error::OddLengthString(n) => Error29::OddLengthString(n),
-                    Error::InvalidLength(m, n) => Error29::InvalidLength(m, n),
-                }));
-                bitcoin::hashes::hex::FromHex::from_byte_iter(iter).map_err(|err| match err {
-                    Error29::InvalidChar(n) => Error::InvalidChar(n),
-                    Error29::OddLengthString(n) => Error::OddLengthString(n),
-                    Error29::InvalidLength(m, n) => Error::InvalidLength(m, n),
-                })
-            }
-        }
-    }
-}
-
-impl_from_bitcoin29_hex!(bitcoin::BlockHash);
-impl_from_bitcoin29_hex!(bitcoin::ScriptBuf);
-impl_from_bitcoin29_hex!(bitcoin::Txid);
-*/
-
 impl FromHex for Vec<u8> {
     fn from_byte_iter<I>(iter: I) -> Result<Self, Error>
     where