Merge branch 'sr/log-SG-no-textconv' into maint

"git log -S/-G" started paying attention to textconv filter, but there was no way to disable this. Make it honor --no-textconv option. * sr/log-SG-no-textconv: diffcore-pickaxe: unify code for log -S/-G diffcore-pickaxe: fix leaks in "log -S<block>" and "log -G<pattern>" diffcore-pickaxe: port optimization from has_changes() to diff_grep() diffcore-pickaxe: respect --no-textconv diffcore-pickaxe: remove fill_one() diffcore-pickaxe: remove unnecessary call to get_textconv()