Fix internal cts sub plan generation bug

Now the package name is used as the regex pattern "as-is",
hence it's matching more packages than what it actually should.

For example "android.dpi" match "android.dpi2" also

Bug: 17576495
Change-Id: Ifad5cf35c4e7aff1f363e08fcab355016db5c67e
diff --git a/tools/utils/buildCts.py b/tools/utils/buildCts.py
index aa5bbf1..6013050 100755
--- a/tools/utils/buildCts.py
+++ b/tools/utils/buildCts.py
@@ -174,7 +174,7 @@
     plan.Exclude('.*')
     plan.Include(r'com\.android\.cts\.browserbench')
     for package, test_list in flaky_tests.iteritems():
-      plan.Include(package)
+      plan.Include(package+'$')
       plan.IncludeTests(package, test_list)
     self.__WritePlan(plan, 'CTS-flaky')