mysql-test/r/sp-error.result:
  Added test case for BUG#9073.
mysql-test/t/sp-error.test:
  Added test case for BUG#9073.
sql/share/errmsg.txt:
  New error message for duplicate condition handlers in stored procedures.
sql/sp_pcontext.cc:
  Keep track on condition handlers in the same block for error checking.
sql/sp_pcontext.h:
  Keep track on condition handlers in the same block for error checking.
sql/sql_yacc.yy:
  Keep track on condition handlers in the same block for error checking.