Do not croak if expwork dir is already created.

tbsetup/mkexpdir.in

@@ -2,7 +2,7 @@
 
 #
 # EMULAB-COPYRIGHT
-# Copyright (c) 2000-2009 University of Utah and the Flux Group.
+# Copyright (c) 2000-2009, 2011 University of Utah and the Flux Group.
 # All rights reserved.
 #
 use English;
@@ -144,14 +144,13 @@ $experiment->Update({"path" => "$eiddir"}) == 0 or
 #
 # Create the working directory.
 #
-if (-e $workdir) {
-    fatal("$workdir already exists!", -1);
-}
-if (! mkdir($workdir, 0775)) {
-    fatal("Could not create $workdir: $!");
-}
-if (! chown($UID, $unix_gid, "$workdir")) {
-    fatal("Could not chown $workdir to $UID/$unix_gid: $!");
+if (! -e $workdir) {
+    if (! mkdir($workdir, 0775)) {
+	fatal("Could not create $workdir: $!");
+    }
+    if (! chown($UID, $unix_gid, "$workdir")) {
+	fatal("Could not chown $workdir to $UID/$unix_gid: $!");
+    }
 }
 
 #