Perms set on log file directory was too strict, server was not allowed
to write to log file.

Also fix perms on datadir as socket file might be inside and perms set
on mysql-files directory.

Signed-off-by: Terje Røsten <terje.rosten@oracle.com>
(cherry picked from commit 4d99bc6ecfb5d31616adac74e5386a9919beb678)