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_unittest.py b/devserver_unittest.py
index bfcd85c..815b5d7 100755
--- a/devserver_unittest.py
+++ b/devserver_unittest.py
@@ -6,16 +6,17 @@
 
 """Regression tests for devserver."""
 
+from xml.dom import minidom
 import json
 import os
-import signal
 import shutil
+import signal
 import subprocess
 import sys
 import time
 import unittest
 import urllib2
-from xml.dom import minidom
+
 
 # Paths are relative to this script's base directory.
 STATIC_DIR = 'static'