title: Embedded expressions with karate DSL don't replace value in json
body: <p>so basically I am just starting with karate testing framework and and probably missing something really simple, but I cant seem to get an embedded expression to be resolved properly. If I have a feature file like so that does the same thing a couple ways: </p>
  
  <pre><code>Feature: Test Service
  
    Background:
      * url 'http://testurl:8080'
      * def localDateTime = Java.type('java.time.LocalDateTime')
  
    Scenario: Successful request
  
      * def createDateTime = LocalDateTime.now()
      * def testRequest =
      """
      {
        createDateTime: "#(createDateTime)",
        expiryDateTime:"#(localDateTime.now().plusMinutes(5))"
      }
      """
      * print testRequest
      * set testRequest.createDateTime = createdTime
      * print testRequest
  </code></pre>
  
  <p>Then when it gets to the print lines, I get output like this where the values are empty js objects {}</p>
  
  <blockquote>
    <p>16:43:28.580 [main] INFO com.intuit.karate - [print] {"createDateTime":{},"expiryDateTime":{}}16:43:28.586 [main] DEBUG com.jayway.jsonpath.internal.PathCompiler - Using cached path: $true[]</p>
  </blockquote>
  
  <p>Also, I can see where it appears to be setting the path for the first print statement like so: </p>
  
  <blockquote>
    <p>16:32:30.612 [main] DEBUG com.jayway.jsonpath.internal.CompiledPath - Evaluating path: $['createDateTime']
    16:32:30.613 [main] DEBUG com.jayway.jsonpath.internal.JsonReader - Set path $['createDateTime'] new value 2017-09-14T16:32:30.566
    16:32:30.629 [main] DEBUG com.jayway.jsonpath.internal.CompiledPath - Evaluating path: $['expiryDateTime']
    16:32:30.629 [main] DEBUG com.jayway.jsonpath.internal.JsonReader - Set path $['expiryDateTime'] new value 2017-09-14T16:37:30.621</p>
  </blockquote>
  
  <p>Can anybody please explain to me why I am unable to get the actual dates inserted into the testRequest?   </p>
  
  <p>Thank you.</p>