Comment 5 for bug 1465317

MacBook-Pro:~ fenris$ brew uninstall juju
Uninstalling /usr/local/Cellar/juju/1.24.3... (4 files, 113M)
juju 1.16.5, 1.16.6, 1.18.3, 1.20.1, 1.20.10, 1.20.11, 1.20.13, 1.20.14, 1.20.7, 1.20.8, 1.21.1, 1.21.3, 1.22.0, 1.22.1, 1.23.3, 1.24.0 are still installed.
Remove them all with `brew uninstall --force juju`.
MacBook-Pro:~ fenris$ brew uninstall --force juju
Uninstalling juju... (59 files, 752M)
MacBook-Pro:~ fenris$ juju
-bash: /usr/local/bin/juju: No such file or directory
MacBook-Pro:~ fenris$ brew install juju
Warning: You are using OS X 10.11.
We do not provide support for this pre-release version.
You may encounter build failures or other breakage.
==> Downloading https://launchpad.net/juju-core/1.24/1.24.3/+download/juju-core_1.24.3.tar.gz
Already downloaded: /Library/Caches/Homebrew/juju-1.24.3.tar.gz
==> go build github.com/juju/juju/cmd/juju
==> go build github.com/juju/juju/cmd/plugins/juju-metadata
==> Caveats
Bash completion has been installed to:
  /usr/local/etc/bash_completion.d
==> Summary
🍺 /usr/local/Cellar/juju/1.24.3: 4 files, 113M, built in 2.9 minutes
MacBook-Pro:~ fenris$ juju
panic: osVersion reported an error: unknown series ""

goroutine 1 [running]:
github.com/juju/juju/version.mustOSVersion(0x0, 0x0)
 /private/tmp/juju20150801-78149-8o11fr/juju-core_1.24.3/src/github.com/juju/juju/version/osversion.go:26 +0xed
github.com/juju/juju/version.init()
 /private/tmp/juju20150801-78149-8o11fr/juju-core_1.24.3/src/github.com/juju/juju/version/version.go:36 +0x478
github.com/juju/juju/tools.init()
 /private/tmp/juju20150801-78149-8o11fr/juju-core_1.24.3/src/github.com/juju/juju/tools/tools.go:20 +0x54
main.init()
 /private/tmp/juju20150801-78149-8o11fr/juju-core_1.24.3/src/github.com/juju/juju/cmd/juju/upgradejuju.go:417 +0x50

MacBook-Pro:~ fenris$ uname -a
Darwin MacBook-Pro.local 15.0.0 Darwin Kernel Version 15.0.0: Tue Jul 21 21:47:25 PDT 2015; root:xnu-3247.1.68~32/RELEASE_X86_64 x86_64