Code review comment for lp:~laurynas-biveinis/percona-xtrabackup/bug1098498-1132763-2.0

I went through the remaining stop_server occurrences and I see no reason to keep them. But then, if we don't really need stop_server, why not just make it do "kill -9" and avoid mass changes in test files?

*If* we ever need to stop the server and keep its data in a test case, then we can add either a new function, or a flag to stop_server.