log: do not override other filtering and sorting options by --bookmark This basically reimplements 0aa118f18d4b 'log: add bookmark option to "hg log"'. Before, any other filtering options but --rev were ignored. -G didn't work either since the ordering constraint wasn't enforced.

scmutil: extract function that builds revset expr to select bookmark branch This is needed to process "log -B" option properly. "log" options have to be translated to a revset expression, not to an evaluated set.