bzr push into mysql-trunk branch (frazer.clement:3767 to 3768)

[Frazer Clement]

 3768 Frazer Clement	2012-05-09
      Empty commit

 3767 Alexander Barkov	2012-05-02
      After-fix for WL#946
      check_simple_equality() didn't work well with
      temporal arguments in some cases, which made
      redundant warnings get produced.
      Fixing agg_arg_charsets_for_comparison() to store its
      result into cmp.cmp_collation instead of a temporary
      variable, so Item_bool_func2::compare_collation()
      returns a correct result.

    modified:
      mysql-test/r/type_temporal_fractional.result
      sql/item_cmpfunc.cc
No bundle (reason: useless for push emails).