tools: Replace log4j with JUL as backend for engine-config

1) Replaces log4j with java.util.logging as logging backend in
   engine-config.

2) Removes --log4j-config param from engine-config. It's not needed
   anymore, because custom logging configuration can be specified
   using OVIRT_LOGGING_PROPERTIES environment variable.

Change-Id: I2b340115f68cf88b6ebd3166044f974fed9e798b
Bug-Url: https://bugzilla.redhat.com/1109871
Signed-off-by: Martin Perina <mperina@redhat.com>