Allow openrc to be loaded in zsh

This fix the test then detect OSX in GetOSVersion that break support of zsh.

Fixes bug #1233118

Change-Id: If243fbe59f8f08041327057425018d7ae0d13ab2
Uniquify unsupported distro error message

Change a distro-not-supported error message in lib/horizon so that it
can't be confused with a similar error case in lib/apache.

Change-Id: I1197cb4de1497906e93a2c3ce09c3c06afe03b65
Don't bail when setting up horizon on openSUSE

I85325179f1792d985b0375572abfe8c8a82fecc3 accidentally removed the
conditional branch required to prevent setup of horizon aborting on
openSUSE, so put it back in.

Change-Id: Ia3e4464a2d718e402d84a0bcf60f13ef30404969
Merge "Allow openrc to be loaded in zsh"
Merge "Don't bail when setting up horizon on openSUSE"
Merge "Uniquify unsupported distro error message"