Remove unused BlockStatus::Pending (#9447)

Pending case never instantiated, and only ever matched together with Unknown

ethcore/sync/src/block_sync.rs

@@ -266,7 +266,7 @@ impl BlockDownloader {
 				BlockStatus::Bad => {
 					return Err(BlockDownloaderImportError::Invalid);
 				},
-				BlockStatus::Unknown | BlockStatus::Pending => {
+				BlockStatus::Unknown => {
 					headers.push(info);
 					hashes.push(hash);
 				}

ethcore/sync/src/chain/handler.rs

@@ -261,7 +261,7 @@ impl SyncHandler {
 				BlockStatus::Queued => {
 					trace!(target: "sync", "New hash block already queued {:?}", hash);
 				},
-				BlockStatus::Unknown | BlockStatus::Pending => {
+				BlockStatus::Unknown => {
 					new_hashes.push(hash.clone());
 					if number > max_height {
 						trace!(target: "sync", "New unknown block hash {:?}", hash);