Forgot to check if some things are null

[chrismin13]

Thanks to IngoRush for reporting this!

[ERROR] Error occurred while disabling AdditionsAPI v1.3.2 (Is it up to date?)

java.lang.NullPointerException: null

at us.fihgu.toolbox.http.HTTPServer.stopServer(HTTPServer.java:116) ~[?:?]

at us.fihgu.toolbox.resourcepack.ResourcePackServer.stopServer(ResourcePackServer.java:67) ~[?:?]

at com.chrismin13.additionsapi.AdditionsAPI.onDisable(AdditionsAPI.java:182) ~[?:?]

at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:256) ~[spigot-1.13.2.jar:git-Spigot-078a7f5-a3c2ec0]

at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:363) [spigot-1.13.2.jar:git-Spigot-078a7f5-a3c2ec0]

at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:422) [spigot-1.13.2.jar:git-Spigot-078a7f5-a3c2ec0]

at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:415) [spigot-1.13.2.jar:git-Spigot-078a7f5-a3c2ec0]

at org.bukkit.craftbukkit.v1_13_R2.CraftServer.disablePlugins(CraftServer.java:368) [spigot-1.13.2.jar:git-Spigot-078a7f5-a3c2ec0]

at net.minecraft.server.v1_13_R2.MinecraftServer.stop(MinecraftServer.java:625) [spigot-1.13.2.jar:git-Spigot-078a7f5-a3c2ec0]

at net.minecraft.server.v1_13_R2.MinecraftServer.run(MinecraftServer.java:770) [spigot-1.13.2.jar:git-Spigot-078a7f5-a3c2ec0]

at java.lang.Thread.run(Thread.java:748) [?:1.8.0_172]