The Chromoting Keystone installer scripts always return the same error code ("1") when there is a problem. This results in all of our install errors being combined into a single value in our dashboard.

Instead, we should:
(1) Use different error codes for each error path.
(2) Avoid using an error code of "1" since that is returned by the Keystone updater (vs. our install script). The 2 different "1"s will be plotted separately, but it is confusing to see 2 lines with the same label (since the source of the "1" is not labelled on the graph).

For reference:

Our install script:
https://cs.chromium.org/chromium/src/remoting/host/installer/mac/Scripts/remoting_preflight.sh

Chrome's install script:
https://cs.chromium.org/chromium/src/chrome/installer/mac/keystone_install.sh