[autotest] Stage debug symbols on-demand before symbolicating minidumps.

We can't stage debug symbols up front, sadly.  So, stage them on-demand iff
we actually get crashes during a test.  Do so in a blocking fashion.

BUG=chromium-os:30400
TEST=set up a dev server that does not have symbols staged, and run a test
TEST=that generates a crash dump.  The symbols should get staged and the dump
TEST=symbolicated.  Now run another.  The symbols should be re-used.

CQ-DEPEND=Ie460526396d2b9999137142c723b87793bc23aaa

Change-Id: I02b69ed2db7b22a557d94a2005fc1cef901eefcd
Reviewed-on: https://gerrit.chromium.org/gerrit/21826
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Ready: Chris Masone <cmasone@chromium.org>
Tested-by: Chris Masone <cmasone@chromium.org>
diff --git a/server/cros/dynamic_suite_unittest.py b/server/cros/dynamic_suite_unittest.py
index 68cac86..552917f 100755
--- a/server/cros/dynamic_suite_unittest.py
+++ b/server/cros/dynamic_suite_unittest.py
@@ -607,7 +607,9 @@
                              mox.StrContains(test.name)),
                 control_type=mox.IgnoreArg(),
                 meta_hosts=[dynamic_suite.VERSION_PREFIX + self._BUILD],
-                dependencies=[]).AndReturn(FakeJob())
+                dependencies=[],
+                keyvals={'build': self._BUILD, 'suite': self._TAG}
+                ).AndReturn(FakeJob())
 
 
     def testScheduleTests(self):