force flush on temp file during consumption

file.write() does not guarantee that a file handle contains anything
without calling an accompanying file.flush()
For typical files that are larger than the OS-file buffer, this is no
problem
For small files (e.g. 64 characters in a .TXT), this race condition
leads to `inode/x-empty` because the file inode is created, but no
content is written to it

ansible/molecule/default/verify.yml

@@ -29,9 +29,9 @@
           document:
             content: "{{ content }}"
             filename: "{{ filename }}.txt"
-            mime_type: text/plain
         headers:
           Authorization: 'Basic {{ (paperlessng_superuser_name + ":" + paperlessng_superuser_password) | b64encode }}'
+          Content-Type: text/plain
         return_content: yes
       register: post_document
       failed_when: "'OK' not in post_document.content"
@@ -45,10 +45,6 @@
       register: logs
       failed_when: "('Consuming ' + filename + '.txt') not in logs.content"
 
-    - name: sleep 5 seconds
-      pause:
-        seconds: 5
-
     - name: verify uploaded document has been consumed
       uri:
         url: "http://{{ paperlessng_listen_address }}:{{ paperlessng_listen_port }}/api/logs/"