Fix high precision timestamps for UI logs matching

Fuel UI relies on the fixed timestamp pattern, so we have to
enable it back in syslog logging config.

Closes-bug: #1328877

Change-Id: Ib12779470f6bf91d26fbfa271c2af14e61535c54
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Merge "Fix high precision timestamps for UI logs matching"