Create the directory where the tarfile is to be unpacked. Not sure why

this was never done ... I guess no one uses tarfiles much.

os/install-tarfile

 #!/usr/bin/perl -wT
 #
 # EMULAB-COPYRIGHT
-# Copyright (c) 2000-2004 University of Utah and the Flux Group.
+# Copyright (c) 2000-2005 University of Utah and the Flux Group.
 # All rights reserved.
 #
 use English;
@@ -135,8 +135,9 @@ else {
 #
 # Make sure the installdir exists!
 #
-if (! -d $installdir) {
-    fatal("$installdir does not exist or is not accessible!");
+if (! -d $installdir &&
+    ! mkdir($installdir, 0775)) {
+    fatal("Could not make directory $installdir: $!");
 }
 
 #