Fix various issues with `gn analyze`.

I had the name of one of the input fields wrong, and I had
an error case not returning output correctly.

R=brettw@chromium.org
BUG=555273

Review-Url: https://codereview.chromium.org/2341683006
Cr-Original-Commit-Position: refs/heads/master@{#419075}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: ac5096069eaa4a7716f6441a1af04e59b635adb7
4 files changed
tree: c56ebb91f51f1b1765ab474dded0c9e5dcbdf5da
  1. tools/