cloud/bmaas/server: do not start BMDB session per RPC

Fixes https://github.com/monogon-dev/monogon/issues/198

Change-Id: Ia99b9a47bfc9ae6de0b9e12e13add891dea289a5
Reviewed-on: https://review.monogon.dev/c/monogon/+/1567
Reviewed-by: Leopold Schabel <leo@monogon.tech>
Tested-by: Jenkins CI
diff --git a/cloud/bmaas/server/BUILD.bazel b/cloud/bmaas/server/BUILD.bazel
index aa4d898..4303d62 100644
--- a/cloud/bmaas/server/BUILD.bazel
+++ b/cloud/bmaas/server/BUILD.bazel
@@ -15,6 +15,7 @@
         "//cloud/bmaas/server/api",
         "//cloud/lib/component",
         "//metropolis/node/core/rpc",
+        "@com_github_cenkalti_backoff_v4//:backoff",
         "@com_github_google_uuid//:uuid",
         "@io_k8s_klog//:klog",
         "@io_k8s_klog_v2//:klog",