remove useless imports

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

Author: koushiro

substrate-archive/src/database.rs

@@ -270,5 +270,4 @@ impl Insert for Metadata {
 #[cfg(test)]
 mod tests {
 	//! Must be connected to a local database
-	use super::*;
 }

substrate-archive/src/database/queries.rs

@@ -220,6 +220,4 @@ pub(crate) async fn get_all_blocks<B: BlockT + DeserializeOwned>(
 #[cfg(test)]
 mod tests {
 	//! Must be connected to a postgres database
-	use super::*;
-	// use diesel::test_transaction;
 }