fix bug when using layer without having deps

Author: eahefnawy

package.json

@@ -1,6 +1,6 @@
 {
  "name": "@serverless/aws-lambda",
- "version": "0.1.4",
+ "version": "0.1.5",
  "main": "./serverless.js",
  "publishConfig": {
  "access": "public"

serverless.js

@@ -1,7 +1,7 @@
 const path = require('path')
 const aws = require('aws-sdk')
 const { mergeDeepRight, pick } = require('ramda')
-const { Component, hashFile } = require('@serverless/components')
+const { Component, hashFile, dirExists } = require('@serverless/components')
 const {
  createLambda,
  updateLambda,
@@ -56,7 +56,11 @@ class AwsLambda extends Component {
 
  config.role = config.role || (await awsIamRole(config))
 
- if (config.bucket && config.runtime === 'nodejs8.10') {
+ if (
+ config.bucket &&
+ config.runtime === 'nodejs8.10' &&
+ (await dirExists(path.join(config.code, 'node_modules')))
+ ) {
  const layer = await this.load('@serverless/aws-lambda-layer')
 
  const layerInputs = {