devtools: fix unused import and whitespace in `android_shell.py`.

R=qsr@chromium.org

Review URL: https://codereview.chromium.org/1421483006 .

Cr-Mirrored-From: https://github.com/domokit/mojo
Cr-Mirrored-Commit: 5efd3908816d6aa5111e6fe745bf4fccc1247b16

devtoolslib/android_shell.py

diff --git a/devtoolslib/android_shell.py b/devtoolslib/android_shell.py
index ab03bb2..91c26af 100644
--- a/devtoolslib/android_shell.py
+++ b/devtoolslib/android_shell.py
@@ -4,7 +4,6 @@
 
 import atexit
 import hashlib
-import json
 import logging
 import os
 import os.path
@@ -67,6 +66,7 @@
   netstat_output = subprocess.check_output(['netstat'])
   return _find_available_port(netstat_output)
 
+
 def parse_adb_devices_output(adb_devices_output):
   """Parses the output of the `adb devices` command, returning a dictionary
   mapping device id to the status of the device, as printed by `adb devices`.