[autotest] Allow for some failure in reimaging DUTs.

Return that reimaging succeeded if at least one DUT reimaged
successfully.

BUG=chromium-os:32925
TEST=unit

Change-Id: I276ba89c0388ccc88ed22f8389ee91393aea157b
Reviewed-on: https://gerrit.chromium.org/gerrit/28737
Tested-by: Alex Miller <milleral@chromium.org>
Reviewed-by: Chris Masone <cmasone@chromium.org>
Commit-Ready: Alex Miller <milleral@chromium.org>
diff --git a/server/cros/dynamic_suite/fakes.py b/server/cros/dynamic_suite/fakes.py
index f0a5db3..d94f40f 100644
--- a/server/cros/dynamic_suite/fakes.py
+++ b/server/cros/dynamic_suite/fakes.py
@@ -89,3 +89,14 @@
         return (self.status == status._status and
                 self.hostname in status._test_name and
                 self.reason == status._reason)
+
+
+    def record_all(self, record):
+        pass
+
+
+    def is_good(self):
+        pass
+
+    def name(self):
+        return self.test_name