Revert "[server] Intercept panics when calling Datastore gRPC methods."
Revert "[server] Intercept panics when calling Datastore gRPC methods."

This reverts commit 841e45aade008f3656cbd64c8471707aaeced2a7.

Reason for revert: no longer needed

Original change's description:
> [server] Intercept panics when calling Datastore gRPC methods.
>
> To debug mysterious Commit failures in Buildbucket.
>
> R=​iannucci@chromium.org
>
> Change-Id: I7880b280de67d3bcfe8e51f14e7499854b7ab88c
> Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2720353
> Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
> Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@google.com>
> Commit-Queue: Vadim Shtayura <9f116ddb1b24f6fc1916a676eb17161b6c07dfc1@chromium.org>

Change-Id: I0a75219351fa0a83a3e9b210756959ecd5e0bf36
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2728129
Bot-Commit: Rubber Stamper <d516c4cc2192058ab8dae3d306acbdaf2ce6574f@appspot.gserviceaccount.com>
Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@google.com>
Commit-Queue: Vadim Shtayura <9f116ddb1b24f6fc1916a676eb17161b6c07dfc1@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go