devserver: module import cleanup

* Import statements re-grouped: standard lib, third party,
  project-local; separated by a single line, preceded by a single line
  and followed by two lines. Each group is sorted alphabetically.

* Removed unused imports.

BUG=None
TEST=Passes unit tests.

Change-Id: Iee4f78b1256457bd19b2c159a29763ba3404c272
Reviewed-on: https://gerrit.chromium.org/gerrit/33859
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Ready: Gilad Arnold <garnold@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
diff --git a/devserver.py b/devserver.py
index 78020ac..e54932f 100755
--- a/devserver.py
+++ b/devserver.py
@@ -6,7 +6,6 @@
 
 """A CherryPy-based webserver to host images and build packages."""
 
-import cherrypy
 import logging
 import optparse
 import os
@@ -16,6 +15,8 @@
 import tempfile
 import threading
 
+import cherrypy
+
 import autoupdate
 import common_util
 import downloader