Fix for disappearing AlreadySpent error

Fixes buffer misalignment when reading back pruning data.
Everything after the buffer length (8000 bytes) was badly read on
restart, leading to accepting double spends.

store/src/sumtree.rs

@@ -169,7 +169,7 @@ impl RemoveLog {
 	/// Open the remove log file. The content of the file will be read in memory
 	/// for fast checking.
 	fn open(path: String) -> io::Result<RemoveLog> {
-		let removed = read_ordered_vec(path.clone())?;
+		let removed = read_ordered_vec(path.clone(), 12)?;
 		Ok(RemoveLog {
 			path: path,
 			removed: removed,
@@ -366,7 +366,7 @@ where
 		let sz = hs_file.size()?;
 		let record_len = 32 + T::sum_len();
 		let rm_log = RemoveLog::open(format!("{}/{}", data_dir, PMMR_RM_LOG_FILE))?;
-		let prune_list = read_ordered_vec(format!("{}/{}", data_dir, PMMR_PRUNED_FILE))?;
+		let prune_list = read_ordered_vec(format!("{}/{}", data_dir, PMMR_PRUNED_FILE), 8)?;
 
 		Ok(PMMRBackend {
 			data_dir: data_dir,
@@ -507,14 +507,14 @@ where
 }
 
 // Read an ordered vector of scalars from a file.
-fn read_ordered_vec<T>(path: String) -> io::Result<Vec<T>>
+fn read_ordered_vec<T>(path: String, elmt_len: usize) -> io::Result<Vec<T>>
 where
 	T: ser::Readable + cmp::Ord,
 {
 	let file_path = Path::new(&path);
 	let mut ovec = Vec::with_capacity(1000);
 	if file_path.exists() {
-		let mut file = BufReader::with_capacity(8 * 1000, File::open(path.clone())?);
+		let mut file = BufReader::with_capacity(elmt_len * 1000, File::open(path.clone())?);
 		loop {
 			// need a block to end mutable borrow before consume
 			let buf_len = {