Send build revision as json object.

Will cause buildbot exceptions otherwise.

TBR=maruel@chromium.org

Review URL: https://codereview.chromium.org/78843007

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@236437 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/annotated_gclient.py b/annotated_gclient.py
index 1ed0f71..61e0b5d 100755
--- a/annotated_gclient.py
+++ b/annotated_gclient.py
@@ -51,7 +51,7 @@
 
 def emit_buildprops(got_revisions):
   for prop, revision in got_revisions.iteritems():
-    print '@@@SET_BUILD_PROPERTY@%s@%s@@@' % (prop, revision)
+    print '@@@SET_BUILD_PROPERTY@%s@%s@@@' % (prop, json.dumps(revision))
 
 
 def main():