Fix a typo that resulted in no tests to be run in depot_tools. :(

tests/trychange_unittest.py

Index: tests/trychange_unittest.py
diff --git a/tests/trychange_unittest.py b/tests/trychange_unittest.py
index 5575d4be437ad28d634ad77bc84510a0995254d8..22c4e6a574ef2933c2d1e8accf401b9544796628 100755
--- a/tests/trychange_unittest.py
+++ b/tests/trychange_unittest.py
@@ -10,6 +10,7 @@
 # Fixes include path.
 from super_mox import SuperMoxTestBase
 
+import subprocess2
 import trychange
 
 
@@ -17,7 +18,7 @@ class TryChangeTestsBase(SuperMoxTestBase):
   """Setups and tear downs the mocks but doesn't test anything as-is."""
   def setUp(self):
     SuperMoxTestBase.setUp(self)
-    self.mox.StubOutWithMock(trychange.gclient_utils, 'CheckCall')
+    self.mox.StubOutWithMock(subprocess2, 'communicate')
     self.mox.StubOutWithMock(trychange.scm.GIT, 'Capture')
     self.mox.StubOutWithMock(trychange.scm.GIT, 'GenerateDiff')
     self.mox.StubOutWithMock(trychange.scm.GIT, 'GetCheckoutRoot')