Drop warnings from adb shell output

This is a quick and dirty fix for a problem that occurs to me when
trying to run instrumentation tests in a simulator.
For some reason 'pm path org.chromium.content_shell_apk.tests' outputs
a warning message in my environment that confuses the python scripts
and they end up calling md5sum for the root directory which is a bit
slow... The real fix would be to be able drop the stderr of the command
but it needs a lot of plumbing and probably there is not that much chance
that something like that will happen again for someone.

BUG=334439

Review URL: https://codereview.chromium.org/138143019

git-svn-id: http://src.chromium.org/svn/trunk/src/build@247742 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/android_commands.py

@@ -641,6 +641,9 @@ class AndroidCommands(object):
     if "'" in command: logging.warning(command + " contains ' quotes")
     result = self._adb.SendShellCommand(
         "'%s'" % command, timeout_time).splitlines()
+    # TODO(b.kelemen): we should really be able to drop the stderr of the
+    # command or raise an exception based on what the caller wants.
+    result = [ l for l in result if not l.startswith('WARNING') ]
     if ['error: device not found'] == result:
       raise errors.DeviceUnresponsiveError('device not found')
     if log_result: