$ juju kill-controller -y gpfs
panic: interface conversion: interface is nil, not bool

goroutine 1 [running]:
panic(0x2058ca0, 0xc820325540)
	/usr/lib/go-1.6/src/runtime/panic.go:481 +0x3e6
github.com/juju/juju/provider/ec2.validateConfig(0xc82017ac80, 0x0, 0x5b22ec, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/provider/ec2/config.go:154 +0x1352
github.com/juju/juju/provider/ec2.environProvider.Validate(0xc82017ac80, 0x0, 0x60000c82007ef28, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/provider/ec2/provider.go:95 +0x46
github.com/juju/juju/provider/ec2.environProvider.newConfig(0xc82017ac80, 0xc8202baea2, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/provider/ec2/config.go:92 +0x3a
github.com/juju/juju/provider/ec2.awsClients(0xc82017ac80, 0x1, 0x1, 0x4707bb, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/provider/ec2/environ.go:83 +0x45
github.com/juju/juju/provider/ec2.(*environ).SetConfig(0xc82032ad90, 0xc82017ac80, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/provider/ec2/environ.go:98 +0x31
github.com/juju/juju/provider/ec2.environProvider.Open(0xc82017ac80, 0x0, 0x0, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/provider/ec2/provider.go:54 +0x1c8
github.com/juju/juju/provider/ec2.(*environProvider).Open(0x3863668, 0xc82017ac80, 0x0, 0x0, 0x0, 0x0)
	<autogenerated>:103 +0xaf
github.com/juju/juju/environs.New(0xc82017ac80, 0x0, 0x0, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/environs/open.go:21 +0xe0
github.com/juju/juju/cmd/juju/controller.(*destroyCommandBase).getControllerEnvironFromStore(0xc8203ede60, 0x7efcdff50940, 0x3863668, 0x7ffcfe81bdb5, 0x4, 0x0, 0x0, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/cmd/juju/controller/destroy.go:372 +0x23d
github.com/juju/juju/cmd/juju/controller.(*destroyCommandBase).getControllerEnviron(0xc8203ede60, 0x7efcdff50940, 0x3863668, 0x7ffcfe81bdb5, 0x4, 0x7efcdff08558, 0xc82028b3b0, 0x0, 0x0, 0x0, ...)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/cmd/juju/controller/destroy.go:347 +0x7a
github.com/juju/juju/cmd/juju/controller.(*killCommand).Run(0xc8203ede60, 0xc82031a640, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/cmd/juju/controller/kill.go:114 +0x2b9
github.com/juju/juju/cmd/modelcmd.(*sysCommandWrapper).Run(0xc820409a10, 0xc82031a640, 0x0, 0x0)
	<autogenerated>:109 +0x65
github.com/juju/juju/cmd/modelcmd.(*baseCommandWrapper).Run(0xc8203cf0b0, 0xc82031a640, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/cmd/modelcmd/base.go:266 +0xd4
github.com/juju/cmd.(*SuperCommand).Run(0xc82040a120, 0xc82031a640, 0x0, 0x0)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/cmd/supercommand.go:456 +0x688
github.com/juju/cmd.Main(0x7efcdff55070, 0xc82040a120, 0xc82031a640, 0xc82000a1d0, 0x3, 0x3, 0x4b222a)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/cmd/cmd.go:280 +0x2f0
github.com/juju/juju/cmd/juju/commands.main.Run(0x2b51758, 0xc82000a1c0, 0x4, 0x4, 0x24e8770)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/cmd/juju/commands/main.go:149 +0x5bb
github.com/juju/juju/cmd/juju/commands.Main(0xc82000a1c0, 0x4, 0x4, 0xc820000180)
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/cmd/juju/commands/main.go:114 +0x48
main.main()
	/build/juju-core-0a_RMU/juju-core-2.0-beta14/src/github.com/juju/juju/cmd/juju/main.go:27 +0x3b