Fixed cell definition retrieval.

Change-Id: Id51d62b3e2b9fbf5a16345e30a604317d003fa26
diff --git a/utils/warden/src/main/java/org/onlab/warden/Warden.java b/utils/warden/src/main/java/org/onlab/warden/Warden.java
index e1c8f48..f641b71 100644
--- a/utils/warden/src/main/java/org/onlab/warden/Warden.java
+++ b/utils/warden/src/main/java/org/onlab/warden/Warden.java
@@ -199,8 +199,16 @@
         }
     }
 
+    /**
+     * Returns the cell definition of the specified cell.
+     *
+     * @param cellName cell name
+     * @return cell definition
+     */
     private String getCellDefinition(String cellName) {
-        return exec("bin/cell-def " + cellName);
+        CellInfo cellInfo = getCellInfo(cellName);
+        return exec(String.format("ssh %s warden/bin/cell-def %s",
+                                  cellInfo.hostName, cellInfo.cellName));
     }
 
     /**