Fix srv_uptime for rabbit OCF
Fix srv_uptime for rabbit OCF

The original condition for srv_uptime was
if  "x$stime" != "x(null)"
In 6.1 it was changed to the reverse one and should be fixed

Closes-bug: #1417947

Change-Id: Ic11f775acaa19915f2e2a4ce93e24b9884d8d10d
Signed-off-by: Bogdan Dobrelya <0b23cd1e586d5f091fecb3391314c2b9ec1fd641@mirantis.com>

xarses/fuel-library,huntxu/fuel-library,xarses/fuel-library,eayunstack/fuel-library,SmartInfrastructures/fuel-library-dev,eayunstack/fuel-library,eayunstack/fuel-library,ddepaoli3/fuel-library-dev,ddepaoli3/fuel-library-dev,SmartInfrastructures/fuel-library-dev,ddepaoli3/fuel-library-dev,stackforge/fuel-library,SmartInfrastructures/fuel-library-dev,eayunstack/fuel-library,ddepaoli3/fuel-library-dev,xarses/fuel-library,zhaochao/fuel-library,xarses/fuel-library,stackforge/fuel-library,stackforge/fuel-library,zhaochao/fuel-library,huntxu/fuel-library,SmartInfrastructures/fuel-library-dev,eayunstack/fuel-library,huntxu/fuel-library,huntxu/fuel-library,zhaochao/fuel-library,SmartInfrastructures/fuel-library-dev,zhaochao/fuel-library,ddepaoli3/fuel-library-dev,huntxu/fuel-library,zhaochao/fuel-library,stackforge/fuel-library