Fix problem that -log_dir will not be respected when anything is logged before flag.Parse().
Fix problem that -log_dir will not be respected when anything is logged before flag.Parse().

Before this change, premature logging resulted into log files being put in the default location (e.g. /tmp), but not the one specified by the log_dir flag.

After this change, premature logging will not result into the creation of the log files yet. Instead, the log message will be printed to stderr.

kubernetes/klog,going/glog,kubernetes/klog,sitano/glog,winxxp/glog,chinanjjohn2012/glog,snowsnail/glog,youleiy/glog,thomasf/lg,aolu11/glog,viki-org/glog,nckturner/glog,zj8487/glog,hongrich/glog,chinawebeye/glog,bruceauyeung/glog,golang/glog