Fix peeking keeping two timeline update mechanisms in play

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/structures/RoomView.js

@@ -236,6 +236,11 @@ export default createReactClass({
             showReadReceipts: SettingsStore.getValue("showReadReceipts", roomId),
         };
 
+        if (!initial && this.state.shouldPeek && !newState.shouldPeek) {
+            // Stop peeking because we have joined this room now
+            this.context.stopPeeking();
+        }
+
         // Temporary logging to diagnose https://github.com/vector-im/riot-web/issues/4307
         console.log(
             'RVS update:',