applying coding guideline

apps/files/index.php

@@ -72,11 +72,11 @@ foreach( explode( '/', $dir ) as $i ){
 }
 
 // make breadcrumb und filelist markup
-$list = new OCP\Template( "files", "part.list", "" );
+$list = new OCP\Template( 'files', 'part.list', '' );
 $list->assign( 'files', $files );
 $list->assign( 'baseURL', OCP\Util::linkTo('files', 'index.php').'?dir=');
 $list->assign( 'downloadURL', OCP\Util::linkTo('files', 'download.php').'?file=');
-$breadcrumbNav = new OCP\Template( "files", "part.breadcrumb", "" );
+$breadcrumbNav = new OCP\Template( 'files', 'part.breadcrumb', '' );
 $breadcrumbNav->assign( 'breadcrumb', $breadcrumb );
 $breadcrumbNav->assign( 'baseURL', OCP\Util::linkTo('files', 'index.php').'?dir=');
 
@@ -88,7 +88,7 @@ $freeSpace=OC_Filesystem::free_space('/');
 $freeSpace=max($freeSpace,0);
 $maxUploadFilesize = min($maxUploadFilesize ,$freeSpace);
 
-$tmpl = new OCP\Template( "files", "index", "user" );
+$tmpl = new OCP\Template( 'files', 'index', 'user' );
 $tmpl->assign( 'fileList', $list->fetchPage() );
 $tmpl->assign( 'breadcrumb', $breadcrumbNav->fetchPage() );
 $tmpl->assign( 'dir', $dir);