When adding a case log, existing objects could not be displayed anymore!

git-svn-id: http://svn.code.sf.net/p/itop/code/trunk@3457 a333f486-631f-4898-b8df-5754b55c2be0

core/attributedef.class.inc.php

@@ -1993,7 +1993,7 @@ class AttributeCaseLog extends AttributeLongText
 
 	public function FromSQLToValue($aCols, $sPrefix = '')
 	{
-		if (!isset($aCols[$sPrefix]))
+		if (!array_key_exists($sPrefix, $aCols))
 		{
 			$sAvailable = implode(', ', array_keys($aCols));
 			throw new MissingColumnException("Missing column '$sPrefix' from {$sAvailable}");