android: Rename device data dir before removing it in gtests.

Might help with device flakes like:
https://chromium-swarm.appspot.com/task?id=37320a4199090410

Bug: 739899, 748145
Change-Id: I953d60aac73194243b5ae4fd9d875c7833977a1d
Reviewed-on: https://chromium-review.googlesource.com/574872
Commit-Queue: Benjamin Pastene <bpastene@chromium.org>
Reviewed-by: Michael Case <mikecase@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491113}

build/android/pylib/local/device/local_device_gtest_run.py

@@ -292,7 +292,7 @@ class LocalDeviceGtestRun(local_device_test_run.LocalDeviceTestRun):
             host_device_tuples_substituted,
             delete_device_stale=True)
         if not host_device_tuples:
-          dev.RunShellCommand(['rm', '-rf', device_root], check_return=True)
+          dev.RemovePath(device_root, force=True, recursive=True, rename=True)
           dev.RunShellCommand(['mkdir', '-p', device_root], check_return=True)
 
       def init_tool_and_start_servers():