Revert "[autotest] Add shard tables and models to Autotest"

Afe jobs has 7 million rows and adding a column might take  upwards of 20 minutes. I would like to avoid the downtime
during the day, and we need a push asap for a servo fix 
that's affecting cq. Since this isn't critical, I'm moving
it out of the way till we have space for the migrate.

This reverts commit 962e3413dce0a6ea2fb0bed87323655f1641e57c.

Change-Id: I053c59cdab314aa7bab5db37b3a4d7cada1f1c7d
Reviewed-on: https://chromium-review.googlesource.com/213791
Reviewed-by: Prashanth B <beeps@chromium.org>
Commit-Queue: Prashanth B <beeps@chromium.org>
Tested-by: Prashanth B <beeps@chromium.org>
diff --git a/scheduler/scheduler_models.py b/scheduler/scheduler_models.py
index 4e63fd3..73b90fa 100644
--- a/scheduler/scheduler_models.py
+++ b/scheduler/scheduler_models.py
@@ -890,7 +890,7 @@
                'run_verify', 'email_list', 'reboot_before', 'reboot_after',
                'parse_failed_repair', 'max_runtime_hrs', 'drone_set_id',
                'parameterized_job_id', 'max_runtime_mins', 'parent_job_id',
-               'test_retry', 'run_reset', 'timeout_mins', 'shard_id')
+               'test_retry', 'run_reset', 'timeout_mins')
     _timer = stats.Timer("scheduler_models.Job")
 
     # This does not need to be a column in the DB.  The delays are likely to