Don't clobber 'comint-input-autoexpand' in 'read-shell-command'
* lisp/shell.el (shell-completion-vars): Set only the buffer-local value of 'comint-input-autoexpand'. (Bug#34815)
* lisp/shell.el (shell-completion-vars): Set only the buffer-local value of 'comint-input-autoexpand'. (Bug#34815)