telemetry_runner: generate perf results for local runs

Commit 1e5c701acaaf4ae81e232636ce5602f67bb2afaa changed the perf
results output format of telemetry_runner to charts-json, but the
results are only scp'd if the telemetry test is run remotely. We
should also store the perf results if the test is run locally.

BUG=chrome-os-partner:47839
TEST=Run
     `test_that --args="local=True" --board oak --fast <dut ip> \
      telemetry_Benchmarks.octane`
     and verify that results-chart.json exists in the result dir
     after the test passed.

Change-Id: I09a4fd225ddcb92c79c608ffe09862273c0a4651
Signed-off-by: Ricky Liang <jcliang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/332568
Tested-by: Horng-Shyang Liao <hs.liao@mediatek.com>
Reviewed-by: Dan Shi <dshi@google.com>
diff --git a/server/cros/telemetry_runner.py b/server/cros/telemetry_runner.py
index 2adb15b..263d696 100644
--- a/server/cros/telemetry_runner.py
+++ b/server/cros/telemetry_runner.py
@@ -166,11 +166,13 @@
         @returns SCP command to copy the results json to the specified directory.
         """
         scp_cmd = []
-        if self._devserver and perf_results_dir:
-            devserver_hostname = dev_server.DevServer.get_server_name(
-                    self._devserver.url())
+        devserver_hostname = ''
+        if perf_results_dir:
+            if self._devserver:
+                devserver_hostname = dev_server.DevServer.get_server_name(
+                        self._devserver.url()) + ':'
             scp_cmd.extend(['scp',
-                            '%s:%s/results-chart.json' % (
+                            '%s%s/results-chart.json' % (
                                     devserver_hostname, self._telemetry_path),
                             perf_results_dir])