Fix properties in rerun and fuchsia recipes

In fuchsia/rerun:
Passing in a slightly modified version of source_build.input.properties
did not work because of strangeness in python protocol buffer APIs.
Buildbucket.search() returns properties containing struct_pb2.Struct
fields, but buildbucket.schedule() wants well_known_types.Struct fields.
Since the fuchsia/fuchsia recipe gets almost all of its settings
from the spec rather than properties, it's fine to just set the one
property we care about (child_build_id), and let buildbucket set the
rest from the latest buildbucket config.

In fuchsia/fuchsia:
Change the type of the child_build_id property from long (which is
the type used in the python protocl buffer API) to int (which is the
type that gets to the recipe when triggered via BuildBucket).

Bug: 39904
Change-Id: I0fdbd960c97dc8fb660501cd5f20b78feb1b76bc
diff --git a/recipes/fuchsia/fuchsia.py b/recipes/fuchsia/fuchsia.py
index 6ecf753..b3fdf42 100644
--- a/recipes/fuchsia/fuchsia.py
+++ b/recipes/fuchsia/fuchsia.py
@@ -64,9 +64,7 @@
 PROPERTIES = {
     'child_build_id':
         Property(
-            # protocol buffer fields are longs, so we use long so that
-            # we can assign to this directly from a protocol buffer.
-            kind=long,
+            kind=int,
             help=('The buildbucket ID of the child build. If set, '
                   'will use this build instead of launching a new one.'),
             default=None),
@@ -522,7 +520,7 @@
       ]) + spec_data(
           gcs_bucket='gcs-bucket', test_in_shards=False) + test_step_data(
               test_in_shards=False) + api.properties(
-                  child_build_id=child_build.id)
+                  child_build_id=int(child_build.id))
 
   yield api.fuchsia.test(
       'build_only_failed',
diff --git a/recipes/fuchsia/rerun.py b/recipes/fuchsia/rerun.py
index a09bec1..04126f9 100644
--- a/recipes/fuchsia/rerun.py
+++ b/recipes/fuchsia/rerun.py
@@ -49,9 +49,9 @@
         'Failed to find source_build for builder %s/%s/%s' %
         (my_build.builder.project, source_bucket, source_builder))
 
-  rerun_properties = source_build.input.properties
-  rerun_properties['child_build_id'] = source_build.output.properties[
-      'child_build_id']
+  rerun_properties = {
+      'child_build_id': source_build.output.properties['child_build_id']
+  }
   schedule_rerun_request = api.buildbucket.schedule_request(
       source_builder,
       project=my_build.builder.project,