deleted_user_group, was_member, was_admin, and the
options' flags.
* src/userdel.c: Change path_prefix() prototype to return a bool.
* src/userdel.c: Ignore return value of setlocale(),
bindtextdomain(), and textdomain().
* src/userdel.c: Ignore the return value from pam_end() since we
are exiting anyway just afterwards.
* src/userdel.c: Avoid implicit conversion of pointers /
integers / chars to booleans.
* src/userdel.c: Add brackets and parenthesis.
* src/userdel.c: Avoid assignments in comparisons.
* src/userdel.c: Do not ignore the return value of the *_unlock()
functions.