Removed temporary fix for old filenames that used absolute urls pointing to the get file api

web/react/components/file_attachment.jsx

@@ -125,10 +125,6 @@ export default class FileAttachment extends React.Component {
     getFileInfoFromName(name) {
         var fileInfo = utils.splitFileLocation(name);
 
-        // This is a temporary patch to fix issue with old files using absolute paths
-        if (fileInfo.path.indexOf('/api/v1/files/get') !== -1) {
-            fileInfo.path = fileInfo.path.split('/api/v1/files/get')[1];
-        }
         fileInfo.path = utils.getWindowLocationOrigin() + '/api/v1/files/get' + fileInfo.path;
 
         return fileInfo;

web/react/components/file_preview.jsx

@@ -35,12 +35,7 @@ export default class FilePreview extends React.Component {
             var ext = filenameSplit[filenameSplit.length - 1];
             var type = Utils.getFileType(ext);
 
-            // This is a temporary patch to fix issue with old files using absolute paths
-
-            if (filename.indexOf('/api/v1/files/get') !== -1) {
-                filename = filename.split('/api/v1/files/get')[1];
-            }
-            filename = Utils.getWindowLocationOrigin() + '/api/v1/files/get' + filename + '?' + Utils.getSessionIndex();
+            filename = Utils.getFileUrl(filename);
 
             if (type === 'image') {
                 previews.push(