title: Argument type mismatch using nifi template import API
body: <p>I am trying to use the import endpoint of the <a href="https://nifi.apache.org/docs/nifi-docs/rest-api/" rel="nofollow noreferrer">Nifi REST API 1.0</a>. I have exported a template as XML using the UI, and am trying to import it using Postman. The request looks like this:</p>
  
  <pre><code>POST /nifi-api/process-groups/63dcaf98-0158-1000-04da-dd54bbb3a5b8/templates/import HTTP/1.1
  Host: localhost:8080
  Content-Type: application/xml
  Cache-Control: no-cache
  Postman-Token: 37a10e8b-b30d-b5c8-4219-ca1ba34f79da
  
  &lt;?xml version="1.0" ?&gt;
  &lt;template encoding-version="1.0"&gt;
     &lt;description&gt;&lt;/description&gt;
     ...
  &lt;/template&gt;
  </code></pre>
  
  <p>I get <code>400</code> error return, with message <code>argument type mismatch</code>. There's nothing very useful in the nifi-user.log:</p>
  
  <pre><code>2016-11-14 14:58:22,164 INFO [NiFi Web Server-327] org.apache.nifi.web.filter.RequestLogger Attempting request for (anonymous)     POST http://localhost:8080/nifi-api/process-groups/63dcaf98-0158-1000-04da-dd54bbb3a5b8/templates/import (source ip: 127.0.0.1)
   2016-11-14 14:58:22,231 INFO [NiFi Web Server-327] o.a.n.w.a.c.IllegalArgumentExceptionMapper java.lang.IllegalArgumentException: argument type mismatch. Returning Bad Request response.
  </code></pre>
  
  <p>Any ideas what may be causing this, or how I can debug?</p>