Add performance configuration for InnoDB

Added following setting to my.cnf/server.cnf
innodb_buffer_pool_size = 20% of available memory
innodb_flush_method = O_DIRECT
innodb_file_per_table = 1

Change-Id: I392720b3dff860ec1e1416657d7517e7a7041849
Fixes: rhbz#1078999
(cherry picked from commit fa002b8e368b9e65d1aa5d81f4779f74571f86b0)