[fuchsia] Make `pm serve` run silently.

"pm serve" runs reliably and no longer needs to run verbosely.
The remaining issues with amber-based deployments tend to be on the
device, not on the HTTP server.

This change prevents a lot of httpd log spam from being sent to the
console.

Bug: 895627
Change-Id: If5e63785c8d70568bd4b1b99a18f4c59acc2a48e
Reviewed-on: https://chromium-review.googlesource.com/c/1407255
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622272}
diff --git a/build/fuchsia/run_package.py b/build/fuchsia/run_package.py
index 104a837..f144da2dd 100644
--- a/build/fuchsia/run_package.py
+++ b/build/fuchsia/run_package.py
@@ -220,7 +220,7 @@
     serve_port = common.GetAvailableTcpPort()
     pm_serve_task = subprocess.Popen(
         [PM, 'serve', '-d', os.path.join(tuf_root, 'repository'), '-l',
-         ':%d' % serve_port])
+         ':%d' % serve_port, '-q'])
     remote_port = common.ConnectPortForwardingTask(target, serve_port, 0)
     _RegisterAmberRepository(target, tuf_root, remote_port)