Set version in versions map on successful handshake

After extensive review, we want to set this
version to ensure that we have agreement between
the connection itself and other parts of the code
that rely on the versions map to validate user
queries.

Author: michaeljmarshall

src/java/org/apache/cassandra/net/OutboundConnection.java

@@ -1118,11 +1118,7 @@ void onCompletedHandshake(Result<MessagingSuccess> result)
 
                         MessagingSuccess success = result.success();
                         messagingVersion = success.messagingVersion;
-                        // We store the peer's endpoint version, not the version we connect on, which might
-                        // be lower due to our own preferred version. This is indicated in the `InboundConnectionInitator`.
-                        // We assert here to ensure that this assumption holds.
-                        int endpointVersion = settings.endpointToVersion.get(settings.to);
-                        assert messagingVersion <= endpointVersion : "Found " + messagingVersion + " > " + endpointVersion;
+                        settings.endpointToVersion.set(settings.to, messagingVersion);
                         debug.onConnect(success.messagingVersion, settings);
                         state.disconnected().maintenance.cancel(false);
 

test/unit/org/apache/cassandra/net/ConnectionTest.java

@@ -336,6 +336,7 @@ public void testSendSmall() throws Throwable
 
             // Ensure version is the same
             inbound.assertHandlersMessagingVersion(outbound.messagingVersion());
+            Assert.assertEquals(outbound.settings().endpointToVersion.get(endpoint), outbound.messagingVersion());
         });
     }
 
@@ -393,6 +394,7 @@ public long serializedSize(Object noPayload, int version)
 
             // Ensure version is the same
             inbound.assertHandlersMessagingVersion(outbound.messagingVersion());
+            Assert.assertEquals(outbound.settings().endpointToVersion.get(endpoint), outbound.messagingVersion());
         });
     }