bzrp passes unsupported options to pagers other than less
bzrp passes "-F -R -X" options to pagers as assuming that less is set as pager.
However it causes an error with pagers which don't support "-F -R -X" options.
e.g. if lv is set as pager, the output is "lv: unknown option F in argument".
bzrp should pass that options only if less is set as pager.