[autotest] Update suite_preprocessor.py to use only literals

When saving dependencies information, forcing all data to literal types
means that the resulting file can be read in with ast.literal_eval, which
is much safer than using eval().

BUG=chromium-os:22060
TEST=run suite_preprocessor.py and check the output to ensure all data is in literals.

Change-Id: I23ad701b0b44e7c6bed931f96836a87c5f70c488
Reviewed-on: https://gerrit.chromium.org/gerrit/24399
Tested-by: Chris Masone <cmasone@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Ready: Chris Masone <cmasone@chromium.org>
1 file changed