cleanup imports

program/src/close.rs

@@ -1,8 +1,5 @@
 use ore_api::state::Proof;
-use solana_program::{
-    account_info::AccountInfo, entrypoint::ProgramResult, program_error::ProgramError,
-    system_program,
-};
+use solana_program::system_program;
 use steel::*;
 
 /// Close closes a proof account and returns the rent to the owner.