select_index_equal: don't call needless grn_ii_resolve_sel_and()
select_index_equal: don't call needless grn_ii_resolve_sel_and()

It's needless when we use grn_obj_search().

groonga/groonga,groonga/groonga,kenhys/groonga,kenhys/groonga,groonga/groonga,kenhys/groonga,groonga/groonga,groonga/groonga,groonga/groonga,groonga/groonga,kenhys/groonga,kenhys/groonga,kenhys/groonga,groonga/groonga,kenhys/groonga,kenhys/groonga