Fix calling of device.PushChangedFiles in android platform telemetry.

This fixes the call of device.PushChangedFiles; see example of correct usage here: https://code.google.com/p/chromium/codesearch#chromium/src/build/android/provision_devices.py&q=PushChangedFiles

This change should fix the breakage of the chrome-proxy tests that was
introduced in https://codereview.chromium.org/656383002/.

BUG=429313

Review URL: https://codereview.chromium.org/689213002

Cr-Commit-Position: refs/heads/master@{#302556}

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

@@ -410,7 +410,7 @@ class AndroidPlatformBackend(
       profile_base = os.path.basename(profile_parent)
 
     saved_profile_location = '/sdcard/profile/%s' % profile_base
-    self._device.PushChangedFiles(new_profile_dir, saved_profile_location)
+    self._device.PushChangedFiles([(new_profile_dir, saved_profile_location)])
 
     profile_dir = self._GetProfileDir(package)
     self._device.old_interface.EfficientDeviceDirectoryCopy(