Fixed runtime to no longer allow the caching of queries with UDF calls.


mysql-test/r/udf.result:
  Added a test that turns on caching and checks that querys calling UDFs don't get cached.
mysql-test/t/udf.test:
  Added a test that turns on caching and checks that querys calling UDFs don't get cached.
sql/sql_yacc.yy:
  Fixed code to set safe_to_cache_query=0 regardless if the function call is a UDF or SP. Where it was placed previously -- at the very end of the else testing for UDFs -- it only executed the statement if the function call was a stored procedure call.