Compare upload limit against biggest file

When uploading multiple files from the web interface, compare the PHP
upload limit against the largest file, not against the sum of all files.

apps/files/js/file-upload.js

@@ -233,7 +233,8 @@ OC.Upload = {
 						data.originalFiles.selection = {
 							uploads: [],
 							filesToUpload: data.originalFiles.length,
-							totalBytes: 0
+							totalBytes: 0,
+							biggestFileBytes: 0
 						};
 					}
 					var selection = data.originalFiles.selection;
@@ -273,13 +274,15 @@ OC.Upload = {
 
 					// add size
 					selection.totalBytes += file.size;
+					// update size of biggest file
+					selection.biggestFileBytes = Math.max(selection.biggestFileBytes, file.size);
 
-					// check PHP upload limit
-					if (selection.totalBytes > $('#upload_limit').val()) {
+					// check PHP upload limit against biggest file
+					if (selection.biggestFileBytes > $('#upload_limit').val()) {
 						data.textStatus = 'sizeexceedlimit';
 						data.errorThrown = t('files',
 							'Total file size {size1} exceeds upload limit {size2}', {
-							'size1': humanFileSize(selection.totalBytes),
+							'size1': humanFileSize(selection.biggestFileBytes),
 							'size2': humanFileSize($('#upload_limit').val())
 						});
 					}