[autotest] Factor out some result-gathering code

In preparation for some reworking of the way we reimage devices,
factor out the code we use in the Suite class to wait for test results
so that we can re-use it in the Reimager class too.

BUG=chromium-os:22060
TEST=run_suite

Change-Id: I630d64e955c83dfd4e885f13a0500c62e30fe59c
Reviewed-on: https://gerrit.chromium.org/gerrit/26324
Tested-by: Chris Masone <cmasone@chromium.org>
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Ready: Chris Masone <cmasone@chromium.org>
diff --git a/frontend/afe/site_rpc_interface.py b/frontend/afe/site_rpc_interface.py
index 57358ae..57e9fee 100644
--- a/frontend/afe/site_rpc_interface.py
+++ b/frontend/afe/site_rpc_interface.py
@@ -11,6 +11,7 @@
 from autotest_lib.client.common_lib import error, global_config
 from autotest_lib.client.common_lib.cros import dev_server
 from autotest_lib.server.cros import control_file_getter, dynamic_suite
+from autotest_lib.server.cros import job_status
 
 
 # Relevant CrosDynamicSuiteExceptions are defined in client/common_lib/error.py.
@@ -39,7 +40,7 @@
 
 
 def formatted_now():
-    return datetime.datetime.now().strftime(dynamic_suite.TIME_FMT)
+    return datetime.datetime.now().strftime(job_status.TIME_FMT)
 
 
 def get_control_file_contents_by_name(build, board, ds, suite_name):