Merge branch 'issue-55' into '1.6.x'

[dock] Closes #55 by restricting the image search to images with the name containing `beat.env.`

See merge request !23

beat/core/dock.py

@@ -264,7 +264,7 @@ class Host(object):
             logger.error("Failed to retrieve the list of docker images, reason:\n\n%s", stderr)
             return (environments, db_environments)
 
-        images = [ x for x in stdout.split('\n') if x.find('beat') >= 0 ]
+        images = [ x for x in stdout.split('\n') if x.find('beat.env.') >= 0 ]
 
 
         for image in images: