netplay: Fix old clients check in PendingInitialConnect handling

The check to refuse old clients (2.3.7) joining doesn't trigger
`if (connectFailed)` case to remove the failed connection
immediately because of the missing `else` in the initial
version check `if-else` clause, but instead falls through
to the `continue` statement.

Signed-off-by: Pavel Solodovnikov <pavel.al.solodovnikov@gmail.com>

lib/netplay/netplay.cpp

@@ -4034,8 +4034,7 @@ static void NETallowJoining()
 					NETaddSessionBanBadIP(tmp_connectState[i].ip);
 					connectFailed = true;
 				}
-
-				if (tmp_connectState[i].usedBuffer >= 8)
+				else if (tmp_connectState[i].usedBuffer >= 8)
 				{
 					// New clients send NETCODE_VERSION_MAJOR and NETCODE_VERSION_MINOR
 					// Check these numbers with our own.