[autoroll] Only use the Retry4XX client for Gerrit
[autoroll] Only use the Retry4XX client for Gerrit

Change-Id: I2954834b72979c9bc0b178163d73c6b31db509d0
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/438817
Reviewed-by: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@google.com>
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot