[MC-110245] Minecraft 1.11 crashes when Refresh is clicked several times on Multiplayer screen.

What I expected to happen was...:
The server list should have refreshed.

What actually happened was...:
Minecraft crashed and opened a crash report in the Launcher

Steps to Reproduce:
1. Click Multiplayer
2. Click Refresh several times

Description: Ticking screen

java.lang.NullPointerException: Ticking screen
	at io.netty.bootstrap.Bootstrap.checkAddress(Bootstrap.java:273)
	at io.netty.bootstrap.Bootstrap.doConnect(Bootstrap.java:150)
	at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:132)
	at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:113)
	at bnt.b(SourceFile:241)
	at bnt.a(SourceFile:45)
	at bnt$1.a(SourceFile:144)
	at er.l(SourceFile:382)
	at bnt.a(SourceFile:254)
	at bjd.e(SourceFile:115)
	at beq.t(SourceFile:1598)
	at beq.av(SourceFile:967)
	at beq.a(SourceFile:395)
	at net.minecraft.client.main.Main.main(SourceFile:124)