bug#8879: 24.0.50; default value of default-justification considered unsafe

[=160t=11bp=e1n N=11bmec]

When visiting a file with a local value of `default-justification' (set in
the file or in .dir-locals.el), the warning about unsafe local variable
values pops up, no matter what the value is.

One would think there's nothing unsafe about the default (or any other
of the possible) value(s) of default-justification, and it's obviously
quite useful to set it file-locally.

Please add a safe value declaration* to Emacs so the warning doesn't
occur. This applies also to the 23 release (in case there is going to be
one).

* (put 'default-justification 'safe-local-variable 'symbolp)

Thanks,

  =160t=11bp=e1n