Add some more directories to the git ignore list

git-svn-id: http://svn.osgeo.org/qgis/trunk@14720 c8812cc2-4d05-0410-92ff-de0c093fc19c

.gitignore

@@ -6,3 +6,7 @@ desktop.ini
 *~
 api_doc
 build
+ms-windows/Installer-Files/postinstall.bat
+ms-windows/Installer-Files/preremove.bat
+ms-windows/osgeo4w/packages/
+ms-windows/osgeo4w/unpacked/