PRESUBMIT: use "master." prefix in CQ_INCLUDE_TRYBOTS.

native_client_sdk/PRESUBMIT.py

Index: native_client_sdk/PRESUBMIT.py
diff --git a/native_client_sdk/PRESUBMIT.py b/native_client_sdk/PRESUBMIT.py
index 9e551bbbdd9290f263d922184b2c4573a38d1689..fd02d5839d51ea4e23cda0fa84db550893165f72 100644
--- a/native_client_sdk/PRESUBMIT.py
+++ b/native_client_sdk/PRESUBMIT.py
@@ -41,15 +41,15 @@ def CheckChangeOnCommit(input_api, output_api):
 
 def GetPreferredTryMasters(project, change):
   return {
-    'tryserver.chromium.linux': {
+    'master.tryserver.chromium.linux': {
       'linux_nacl_sdk': set(['defaulttests']),
       'linux_nacl_sdk_build': set(['defaulttests']),
     },
-    'tryserver.chromium.win': {
+    'master.ryserver.chromium.win': {
       'win_nacl_sdk': set(['defaulttests']),
       'win_nacl_sdk_build': set(['defaulttests']),
     },
-    'tryserver.chromium.mac': {
+    'master.tryserver.chromium.mac': {
       'mac_nacl_sdk': set(['defaulttests']),
       'mac_nacl_sdk_build': set(['defaulttests']),
     }