Add a mailing list to subscribe to services/network CL reviews

Use network-service-reviews@chromium.org to watch for network service CL reviews.

Change-Id: I4894e393a8933be05dd8e10021346b328598ba3d
Reviewed-on: https://chromium-review.googlesource.com/1052309Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Helen Li <xunjieli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557214}

WATCHLISTS

@@ -1162,6 +1162,9 @@
     'netinfo': {
       'filepath': '/netinfo/',
     },
+    'network_service': {
+      'filepath': 'services/network/',
+    },
     'nfc': {
       'filepath': '/nfc/',
     },
@@ -2191,6 +2194,7 @@
                 'eroman@chromium.org'],
     'net_spdy': ['bnc+watch@chromium.org'],
     'netinfo': ['jkarlin+watch@chromium.org'],
+    'network_service': ['network-service-reviews@chromium.org'],
     'nfc': ['mattreynolds+watch@chromium.org'],
     'notifications': ['awdf+watch@chromium.org', 'peter@chromium.org'],
     'nqe': ['tbansal+watch-nqe@chromium.org'],