DEV-44838 - Fix another bug introduced by passing "executable" in...

DEV-44838 - Fix another bug introduced by passing "executable" in WindowsSetup.run();  find_in_path() does not handle absolute paths, but name is guaranteed to be an absolute path.

This explains the bogus message in the log of the form "process $foo exited with nonzero status; process $foo is not found", described here:
https://jira.lindenlab.com/jira/browse/DEV-44838?focusedCommentId=328441&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_328441