Fix some unnecessary-unwraps w/ addl cleanup/simplification.

Signed-off-by: Jason Volk <jason@zemos.net>

src/service/rooms/timeline/mod.rs

@@ -195,7 +195,7 @@ impl Service {
 		state_lock: &MutexGuard<'_, ()>, // Take mutex guard to make sure users get the room state mutex
 	) -> Result<Vec<u8>> {
 		// Coalesce database writes for the remainder of this scope.
-		let _cork = services().globals.cork_and_flush()?;
+		let _cork = services().globals.db.cork_and_flush();
 
 		let shortroomid = services()
 			.rooms