Fix undefined array key warnings in productos module

Added $info array initialization with default values for proveedorId
and prodCatId to prevent 'Trying to access array offset on null'
warnings in search-productos.tpl and enumProdCatSearch.tpl templates.

modules/productos.php

@@ -29,11 +29,17 @@
 	
 	$categorias = $prodCat->EnumerateAll();
 	$proveedores = $proveedor->EnumerateAll();
-	
+
 	$msg = $_SESSION['msgP'];
 	$_SESSION['msgP'] = '';
-	
-	$smarty->assign('msg', $msg);	
+
+	$info = array(
+		'proveedorId' => '',
+		'prodCatId' => ''
+	);
+
+	$smarty->assign('msg', $msg);
+	$smarty->assign('info', $info);
 	$smarty->assign('categorias', $categorias);
 	$smarty->assign('proveedores', $proveedores);
 	$smarty->assign('productos', $productos);