* lisp/progmodes/sh-script.el: Fix indentation rule of "| while".

Fixes: debbugs:18031

* lisp/progmodes/sh-script.el (sh-smie-sh-rules): Go back to the beginning
of the whole pipe when indenting an opening keyword after a |.
Generalize this treatment to opening keywords like "while".
* src/eval.c (Fsignal): Remove duplicate test.

(Fautoload_do_load): Fix up docstring.