produce warning for 'create database if not exists' if database exists
  do not update database options in this case  
  produce warning for 'create table if not exists' if table exists



mysql-test/r/create.result:
  Fix for bug #6008: MySQL does not create warnings when creating database and using IF NOT EXISTS
    updated test case result
mysql-test/r/temp_table.result:
  Fix for bug #6008: MySQL does not create warnings when creating database and using IF NOT EXISTS
    updated test case result
mysql-test/r/warnings.result:
  Fix for bug #6008: MySQL does not create warnings when creating database and using IF NOT EXISTS
    updated test case result
mysql-test/t/create.test:
  Fix for bug #6008: MySQL does not create warnings when creating database and using IF NOT EXISTS
    test case
sql/sql_db.cc:
  Fix for bug #6008: MySQL does not create warnings when creating database and using IF NOT EXISTS
    produce warning for 'create database if not exists' if database exists
    do not update database options in this case
sql/sql_table.cc:
  Fix for bug #6008: MySQL does not create warnings when creating database and using IF NOT EXISTS
    produce warning for 'create table if not exists' if table exists