Update src/main/java/net/md_5/bungee/InitialHandler.java

Found that when force_default_server is set to true, Its possible for a single user to have multiple connections to different servers connected by BungeeCord. Added in a check to block that.
Merge pull request #1 from pratham2003/patch-1

Update src/main/java/net/md_5/bungee/InitialHandler.java