Fix valid_value print of complex robot var

On error, this line...

    Rvalid Value  os_release_info['version_id']
    ...  valid_values=['${install_version}']

Was printing the variable name as just ['version_id'] rather than
os_release_info['version_id'].

Change-Id: Idd9e268f9d73ac70477ab85eacc5a2392ab8507f
Signed-off-by: Michael Walsh <micwalsh@us.ibm.com>
diff --git a/lib/gen_valid.py b/lib/gen_valid.py
index 882e31d..77099c0 100755
--- a/lib/gen_valid.py
+++ b/lib/gen_valid.py
@@ -161,7 +161,7 @@
         error_message += "The following variable has an invalid" +\
                          " value:\n" +\
                          gp.sprint_varx(get_var_name(var_name), var_value,
-                                        gp.blank()) +\
+                                        gp.blank() | gp.verbose()) +\
                          "\nIt must be one of the following values:\n" +\
                          gp.sprint_var(valid_values, gp.blank())
         return error_message
@@ -176,7 +176,7 @@
 
     error_message += "The following variable has an invalid value:\n" +\
                      gp.sprint_varx(get_var_name(var_name), var_value,
-                                    gp.blank()) +\
+                                    gp.blank() | gp.verbose()) +\
                      "\nIt must NOT be one of the following values:\n" +\
                      gp.sprint_var(invalid_values, gp.blank())
     return error_message