Merge branch 'sb/unpack-trees-super-prefix'

"git read-tree" and its underlying unpack_trees() machinery learned to report problematic paths prefixed with the --super-prefix option. * sb/unpack-trees-super-prefix: unpack-trees: support super-prefix option t1001: modernize style t1000: modernize style read-tree: use OPT_BOOL instead of OPT_SET_INT