#1176: empty placeholders are represented by an empty string as in previous version.

git-svn-id: http://svn.code.sf.net/p/itop/code/trunk@3873 a333f486-631f-4898-b8df-5754b55c2be0

core/dbobject.class.php

@@ -2420,7 +2420,10 @@ abstract class DBObject implements iDisplay
 				$oAttDef = MetaModel::GetAttributeDef(get_class($this), $sAttCode);
 				$ret = $oAttDef->GetForTemplate($this->Get($sAttCode), $sVerb, $this);
 			}
-
+			if ($ret === null)
+			{
+				$ret = '';
+			}
 		}
 		return $ret;
 	}