Fix printf's format specifier: the thread number "nr" is long, not long long. Fixes http://root.cern.ch/phpBB2/viewtopic.php?t=9385
Remove indentation of thread numbers, they all have of single digits only.


git-svn-id: http://root.cern.ch/svn/root/trunk@30980 27541ba8-7e3a-0410-8455-c3a389f83636