Per the commit message of r8514, change the search order to be "ssh :

rsh", *not* "rsh : ssh".

This commit was SVN r8736.

The following SVN revision numbers were found above:
  r8514 --> open-mpi/ompi@9c25bdc5ac

orte/mca/pls/rsh/pls_rsh_component.c

@@ -157,8 +157,8 @@ int orte_pls_rsh_component_open(void)
     mca_pls_rsh_component.assume_same_shell = tmp;
 
     mca_base_param_reg_string(c, "agent",
-                              "The command used to launch executables on remote nodes (typically either \"rsh\" or \"ssh\")",
-                              false, false, "rsh : ssh",
+                              "The command used to launch executables on remote nodes (typically either \"ssh\" or \"rsh\")",
+                              false, false, "ssh : rsh",
                               &mca_pls_rsh_component.agent_param);
 
     return ORTE_SUCCESS;