KIconLoader uses ~/.cache/icon-cache.kcache, and it is opened in
read-write mode. Because access to it does not seem to be critical, and
read-only mode is not used, rules for accessing this cache is added to
it's own new "write" abstraction, instead of making kde abstraction more
permissive by default.
Signed-off-by: John Johansen <john.johansen@canonical.com>
