[Android] Remove EMMA coverage html directory after upload.

BUG=334319
NOTRY=True

Review URL: https://codereview.chromium.org/138503003

git-svn-id: http://src.chromium.org/svn/trunk/src/build@245077 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/buildbot/bb_device_steps.py

@@ -558,6 +558,7 @@ def MainTestWrapper(options):
       coverage_html = GenerateJavaCoverageReport(options)
       UploadHTML(options, '%s/java' % options.coverage_bucket, coverage_html,
                  'Coverage Report')
+      shutil.rmtree(coverage_html, ignore_errors=True)
 
     if options.experimental:
       RunTestSuites(options, gtest_config.EXPERIMENTAL_TEST_SUITES)