travis: tweak logging
We're currently hitting the maximum time limit for jobs (50').
Let's see if reducing log output helps speed them up (less I/O?),
otherwise we may have to disable some tests.
<logger name="jdbc.resultsettable" level="OFF"/>
<logger name="jdbc.connection" level="OFF"/>
+ <logger name="org.apache.shiro.realm.text.IniRealm" level="ERROR"/>
+ <logger name="org.slf4j.Logger" level="ERROR"/>
+
+ <logger name="org.killbill.billing.osgi" level="ERROR"/>
+ <logger name="org.killbill.bus" level="ERROR"/>
+
<root level="WARN">
<appender-ref ref="STDOUT"/>
</root>
