Bazel: Consume global-refdb only from source

The plugin sources are compiled against `global-refdb` built from
source, but the tests were running against the external dependency
fetched from Maven Central.

Stop fetching `global-refdb` as an external dependency and use the
in-tree target consistently for both compilation and test execution.

This plugin currently does not support standalone build mode, so using
the in-tree dependency is acceptable.

Change-Id: I0ede56e6d66b6efdcfd0f592c991b5be90c1b048

BUILD

diff --git a/BUILD b/BUILD
index 3831c0f..14bcf3c 100644
--- a/BUILD
+++ b/BUILD
@@ -54,8 +54,8 @@
     visibility = ["//visibility:public"],
     exports = PLUGIN_DEPS + PLUGIN_TEST_DEPS + [
         ":high-availability__plugin",
+        "//plugins/global-refdb",
         "@failsafe//jar",
-        "@global-refdb//jar",
         "@jgroups//jar",
         "@wiremock//jar",
     ],

external_plugin_deps.bzl

diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 02c1df5..820a05e 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -20,12 +20,6 @@
     )
 
     maven_jar(
-        name = "global-refdb",
-        artifact = "com.gerritforge:global-refdb:3.7.4",
-        sha1 = "a5f3fcdbc04b7e98c52ecd50d2a56424e60b0575",
-    )
-
-    maven_jar(
         name = "failsafe",
         artifact = "dev.failsafe:failsafe:3.3.2",
         sha1 = "738a986f1f0e4b6c6a49d351dddc772d1378c5a8",