Minor tweaks to custom repo hooks.

- Include stderr in error message
- Indent error message to make it easier to read
- Put quotation marks around hook command for clarity

TEST=custom repohook in platform/factory

Change-Id: I9f207a09ba8071eeaf6637bbbb055a924e12b31c
Reviewed-on: https://gerrit.chromium.org/gerrit/31954
Tested-by: Jon Salz <jsalz@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Jon Salz <jsalz@chromium.org>
Commit-Ready: Jon Salz <jsalz@chromium.org>
1 file changed