[ccache] Insufficient environment sanitization in test.sh

[Joel Rosdahl]

On 23 December 2017 at 14:49, Radu Rendec via ccache <ccache at lists.samba.org
> wrote:

> I ran across a weird issue where test.sh fails in the CCACHE_NOHASHDIR
> test because the CCACHE_HASHDIR variable happens to be set in my
> environment.

[...]

My idea is to iterate through the output of `env` and unset all
> variables starting with CCACHE_ instead of listing them explicitly
> (since this is pretty much what conf_update_from_environment() does).
> Any thoughts?
>

Sounds good, I'll fix it. Thanks!

-- Joel