[FIX] fileUtils: Properly handle exceptions from fs.stats

Do not assume every exception is caused by a missing file

lib/fileUtils.js

@@ -10,8 +10,14 @@ module.exports = function(fs) {
 	function statFile(filePath) {
 		return new Promise(function(resolve, reject) {
 			fs.stat(filePath, function(err, stat) {
-				// No rejection here as it is ok if the file was not found
-				resolve(stat ? {path: filePath, stat: stat} : null);
+				if (err instanceof Error) {
+					if (err.code === "ENOENT") { // "File or directory does not exist"
+						return resolve(null);
+					} else {
+						return reject(err);
+					}
+				}
+				resolve(stat ? {path: filePath, stat} : null);
 			});
 		});
 	}