Docker does not output Status after pull anymore.

- Docker 1.12 on CemtoOS7 does not output status line anymore.
- Do not rely on Docker output to verify if the image was the latest.

(cherry picked from commit 5f3c887c38)

lib/ansible/module_utils/docker_common.py

@@ -430,13 +430,10 @@ class AnsibleDockerClient(Client):
         Pull an image
         '''
         self.log("Pulling image %s:%s" % (name, tag))
-        alreadyToLatest = False
+        old_tag = self.find_image(name, tag)
         try:
             for line in self.pull(name, tag=tag, stream=True, decode=True):
                 self.log(line, pretty_print=True)
-                if line.get('status'):
-                    if line.get('status').startswith('Status: Image is up to date for'):
-                        alreadyToLatest = True
                 if line.get('error'):
                     if line.get('errorDetail'):
                         error_detail = line.get('errorDetail')
@@ -448,6 +445,8 @@ class AnsibleDockerClient(Client):
         except Exception as exc:
             self.fail("Error pulling image %s:%s - %s" % (name, tag, str(exc)))
 
-        return self.find_image(name, tag), alreadyToLatest
+        new_tag = self.find_image(name, tag)
+
+        return new_tag, old_tag == new_tag