Add integration test for mysql

[istana]

No description provided.

[istana]

buff_test fails - There is something weird going on with mysql libraries - the the function doesn't get called again when the buffer is too small - tested with fedora, ubuntu:latest and ubuntu:rolling. Works with mariadb libraries though. Why? No idea as it shouldn't depend on mysql/mariadb, but glibc calls the function again.

[istana]

mysql will still not retry with larger buffer in some cases

sys-1       | 
sys-1       | libnss-maria[2288]: /home/libnss-maria/src/mariadb/query.c:59:maria_init_db_conn(): connection initialized successfully
sys-1       | 
sys-1       | libnss-maria[2288]: /home/libnss-maria/src/mariadb/query.c:126:maria_query_with_param(): 
sys-1       | libnss-maria[2288]: SELECT users.username AS username, 'x' AS password, users.id AS uid, users.gid AS gid, users.gecos AS gecos, users.homedir AS homedir, users.shell AS shell FROM users INNER JOIN groups_users ON users.id = groups_users.user_id INNER JOIN `groups` ON groups_users.group_id = groups.id WHERE users.active = 1 AND users.gid = groups.id AND users.username = 'johnsilver_shoozee9shaequ2gi2beechoof3Nuxio4hee7geiDaqu7aezaiyee9aebai6xieF3uez2Oriec3quohjie2Shoh6aiZah7EebohGh0ji8ui6aefoquu3shu9ay0Tee7oakej7the1Aishe0ci8chee5iY3eC9aej1Weuliequai0Nahd3viemaiYeedaehishei0meixiejahghaeCh7Igeijeithohquia8johl8Siechfhfhfh' ORDER BY groups.id LIMIT 1
sys-1       | libnss-maria[2288]: 
sys-1       | 
sys-1       | libnss-maria[2288]: /home/libnss-maria/src/nss/result_handler.c:18:copy_db_row_to_passwd(): 
sys-1       | libnss-maria[2288]: XXXXXXX username:johnsilver_shoozee9shaequ2gi2beechoof3Nuxio4hee7geiDaqu7aezaiyee9aebai6xieF3uez2Oriec3quohjie2Shoh6aiZah7EebohGh0ji8ui6aefoquu3shu9ay0Tee7oakej7the1Aishe0ci8chee5iY3eC9aej1Weuliequai0Nahd3viemaiYeedaehishei0meixiejahghaeCh7Igeijeithohquia8johl8Siechfhfhfh; buflen:1024
sys-1       | libnss-maria[2288]: 
sys-1       | 
sys-1       | libnss-maria[2288]: /home/libnss-maria/src/nss/result_handler.c:22:copy_db_row_to_passwd(): copy_db_row_to_passwd: buffer too small
sys-1       | 
sys-1       | libnss-maria[2288]: /home/libnss-maria/src/nss/passwd.c:50:_nss_maria_getpwnam_r(): 
sys-1       | libnss-maria[2288]: nss_status: -2, errnop: 34, iserange: 1
sys-1       | libnss-maria[2288]: