get strange result
  according to Monty's suggestions, fixing the SELECT behaviour on errors
  with SP handlers. Note that some warnings from SELECT still shows up when
  the handler has caught - this is an effect of another known bug (BUG#7049).


mysql-test/r/sp.result:
  New test cases for BUG#12379.
mysql-test/t/sp.test:
  New test cases for BUG#12379.
sql/sql_class.cc:
  Abort selects on errors more graceful with SP handlers.
sql/sql_class.h:
  Abort selects on errors more graceful with SP handlers.