enforce short hostname on all platforms (especially macbroy2);

--- a/Admin/isatest/isatest-settings	Sat Dec 17 12:42:10 2011 +0100
+++ b/Admin/isatest/isatest-settings	Sat Dec 17 12:51:30 2011 +0100
@@ -35,6 +35,8 @@
 
 DISTPREFIX=$HOME/isadist
 
+HOSTNAME="$(hostname -s)"
+
 # this function avoids NFS inconsistencies with multiple writers by
 # sshing to one central machine and writing locally. There is stil a
 # race condition, but at least it should not corrupt a whole set of entries