[r22842]Clean up some leftovers from 22841

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/maintenance/gramps40@22950 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
[r22949]Bug 7017 GUI stuck when external viewer launched

subprocess.checked_call seems to wait on the process that xdg-open
starts, but subprocess.wait doesn't.

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/maintenance/gramps40@22951 4ae1f11a-8b86-4847-b8af-ab372f36d1fd