hideshow.el: permanent local variables

[Glenn Morris]

hideshow.el gives several variables the permanent-local property:

hs-minor-mode, hs-c-start-regexp, hs-block-start-regexp
hs-block-start-mdata-select, hs-block-end-regexp, hs-forward-sexp-func
hs-adjust-block-beginning

I don't understand why this is desirable; indeed it leads to at least
one problem.

I activate hideshow mode in lisp-based modes with a mode-hook (as per
the suggested usage in the file commentary). When I decide to save my
scratch buffer as a text file, hideshow mode is not killed.

For example, this leads to problems with restoring a desktop:

emacs -q --no-site-file
M-x hs-minor-mode
C-x C-w foo.txt
M-x desktop-save-mode
M-x desktop-save .
M-x desktop-read
   -> "Text Mode doesn't support Hideshow Minor Mode"

This aborts the load of the rest of a desktop.