Telemetry / Android: uses the right adb for CacheControl.

CacheControl takes pylib/android_commands.py.
Broken at https://chromiumcodereview.appspot.com/20766003

BUG=
TBR=simonjam@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23601016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221501 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/core/platform/android_platform_backend.py

@@ -122,7 +122,7 @@ class AndroidPlatformBackend(platform_backend.PlatformBackend):
     return False
 
   def FlushEntireSystemCache(self):
-    cache_control = perf_tests_helper.CacheControl(self._adb.Adb())
+    cache_control = perf_tests_helper.CacheControl(self._adb)
     cache_control.DropRamCaches()
 
   def FlushSystemCacheForDirectory(self, directory, ignoring=None):