cbuildbot: Remove tryjob request logic from cbuildbot.

Now that tryjobs are no longer supported, strip out the assorted logic
needed to support them.

BUG=chromium:762676
TEST=run_tests

Change-Id: I41b49dc15c39832de98280f3b04d974754a79bc6
Reviewed-on: https://chromium-review.googlesource.com/653594
Commit-Ready: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
diff --git a/scripts/cbuildbot_unittest.py b/scripts/cbuildbot_unittest.py
index 9b175f9..9156998 100644
--- a/scripts/cbuildbot_unittest.py
+++ b/scripts/cbuildbot_unittest.py
@@ -21,7 +21,7 @@
   def testIsDistributedBuilder(self):
     """Tests for _IsDistributedBuilder() under various configurations."""
     parser = cbuildbot._CreateParser()
-    argv = ['amd64-generic-paladin']
+    argv = ['--buildroot', '/foo', 'amd64-generic-paladin']
     options = cbuildbot.ParseCommandLine(parser, argv)
     options.buildbot = False