tests: increase sleep time in system_scrubber test
tests: increase sleep time in system_scrubber test

jswrenn/xtreemfs,rbaerzib/xtreemfs,kleingeist/xtreemfs,harnesscloud/xtreemfs,stanik137/xtreemfs,kleingeist/xtreemfs,harnesscloud/xtreemfs,jswrenn/xtreemfs,jswrenn/xtreemfs,rbaerzib/xtreemfs,stanik137/xtreemfs,kleingeist/xtreemfs,harnesscloud/xtreemfs,kleingeist/xtreemfs,rbaerzib/xtreemfs,rbaerzib/xtreemfs,harnesscloud/xtreemfs,stanik137/xtreemfs,jswrenn/xtreemfs,harnesscloud/xtreemfs,harnesscloud/xtreemfs,harnesscloud/xtreemfs,kleingeist/xtreemfs,rbaerzib/xtreemfs,jswrenn/xtreemfs,kleingeist/xtreemfs,stanik137/xtreemfs,stanik137/xtreemfs,stanik137/xtreemfs,rbaerzib/xtreemfs,kleingeist/xtreemfs,stanik137/xtreemfs,kleingeist/xtreemfs,rbaerzib/xtreemfs,jswrenn/xtreemfs,jswrenn/xtreemfs,harnesscloud/xtreemfs,stanik137/xtreemfs,jswrenn/xtreemfs,rbaerzib/xtreemfs