remove impossible panickers related to infallible db transaction (#1947)

util/src/migration/mod.rs

@@ -75,7 +75,7 @@ impl Batch {
 		let transaction = DBTransaction::new(dest);
 
 		for keypair in &self.inner {
-			try!(transaction.put(self.column, &keypair.0, &keypair.1).map_err(Error::Custom));
+			transaction.put(self.column, &keypair.0, &keypair.1);
 		}
 
 		self.inner.clear();

util/src/migration/tests.rs

@@ -37,7 +37,7 @@ fn make_db(path: &Path, pairs: BTreeMap<Vec<u8>, Vec<u8>>) {
 	{
 		let transaction = db.transaction();
 		for (k, v) in pairs {
-			transaction.put(None, &k, &v).expect("failed to add pair to transaction");
+			transaction.put(None, &k, &v);
 		}
 
 		db.write(transaction).expect("failed to write db transaction");