fix bug in guessing line ending

tasks/injector.js

@@ -59,6 +59,7 @@ module.exports = function(grunt) {
       var that = this;
       options.lineEnding = getDefaultLineEnding(options, that, grunt);
     }
+
 
     // Iterate over all specified file groups and gather files to inject:
 
@@ -296,16 +297,18 @@ function getDefaultLineEnding(options, that, grunt) {
   // when destination file is a template
   var destination = options.template || options.templateString;
 
-  // when destination file is destFile
-  if (options.destFile) {
-    destination = options.destFile;
-  } else {
-    //if the destination file does not exist yet
-	  // try to figure out lineEnding through src files
-    if (!grunt.file.exists(that.files[0].dest)) {
-      destination = that.filesSrc[0];
+  // if destination file not found, try to guess from destFile
+  if (typeof destination === 'undefined') {
+    if (options.destFile && grunt.file.exists(that.files[0].dest)) {
+      destination = options.destFile;
     } else {
-      destination = that.files[0].dest;
+      //if the destination file does not exist yet
+      // try to figure out lineEnding through src files
+      if (!grunt.file.exists(that.files[0].dest)) {
+        destination = that.filesSrc[0];
+      } else {
+        destination = that.files[0].dest;
+      }
     }
   }
 
@@ -318,6 +321,6 @@ function getDefaultLineEnding(options, that, grunt) {
       contents = String(grunt.file.read(destination));
     }
   }
-
+  
   return /\r\n/.test(contents) ? '\r\n' : '\n';
 }