Update tegra2 preflight to push to FULL_BINHOST on 0.15.877.B.

BUG=chrome-os-partner:5659
TEST=cbuildbot_config_unittest

Change-Id: I11e49e35a8376d9bfb60d63afd9320feea70e766
Reviewed-on: http://gerrit.chromium.org/gerrit/7176
Reviewed-by: Dave Parker <dparker@chromium.org>
Tested-by: David James <davidjames@chromium.org>
diff --git a/buildbot/cbuildbot_config.py b/buildbot/cbuildbot_config.py
index 0222c3d..f713846 100644
--- a/buildbot/cbuildbot_config.py
+++ b/buildbot/cbuildbot_config.py
@@ -495,6 +495,7 @@
   'vm_tests' : False,
   'prebuilts' : True,
   'git_sync': True,
+  'binhost_key': 'FULL_BINHOST',
 }])
 
 add_config('arm-tegra2_seaboard-private-bin', [internal, arm, binary, {