needed to be fixed in earlier versions)
Fixed the iteration of how substrings are handled with negative indexes in 
SUBSTRING_INDEX


mysql-test/r/func_str.result:
  New results for the fix to substring_index
mysql-test/t/func_str.test:
  Added tests for fix to substring_index, various lenth search patterns. Also included
  are the queuries the user who reported the bug listed in the bug report
sql/item_strfunc.cc:
  Fix to BUG 11104 
      Took out the offset-=delimiter_length-1 out of the for loop. It was causing
      basically this: 
      select substring_index('the king of the the hill', 'the', -2) to not work.
      The first iteration, offset would be initialised to 24, then strstr would 
      point at 'the king of the the* hill' ('*'means right before the 
      character following), returning a offset of 16. The for loop would then 
      decrement offset by two (3 - 1), to 14, now pointing at 
      "the king of th*e the hill", _skipping_ past the 'e' in the second to last
      'the', and therefore strstr would never have a chance of matching the 
      second to last 'the', then moving on to the 'the' at the begginning of the 
      string!
  
      In a nutshell, offset was being decremented by too great a value, preventing
      the second to last 'the' from being ever found, hence the result of 
      'king of the the hill' from the query that is reported in the bug report