* breakpoint.c (bpstat_do_actions): To ensure that

* breakpoint.c (bpstat_do_actions): To ensure that
clear_proceed_status doesn't free the command tree we're
evaluating out from under us, zero the bpstat's pointer to it, and
take care of freeing it ourselves.
* cli/cli-script.c (make_cleanup_free_command_lines): Make this
function externally visible.
* cli/cli-script.h (make_cleanup_free_command_lines): New
declaration.