Reapply fix made in commit 217010d that prevents file corruption from additional line return characters appended to the file contents.

Author: jperezq

forcetk.js

@@ -301,7 +301,7 @@ if (forcetk.Client === undefined) {
                     + "Content-Disposition: form-data; name=\"" + payloadField
                     + "\"; filename=\"" + filename + "\"\n\n",
                 payload,
-                "\n\n"
+                "\n"
                     + "--boundary_" + boundary + "--"
             ], {type : 'multipart/form-data; boundary=\"boundary_' + boundary + '\"'}),
             request = this.getXHR();