Don't auto-configure plugin for upgrades

If high-availability.config is present, do not overwrite the current
configuration during the upgrade init step.

Bug: Issue 11781
Change-Id: Id76feaf3a1cc8ad5240da194769303c595fa8f8f
(cherry picked from commit 9cf2eafea86bfc3f8299fc6308b7f43a10753ff4)

src/main/java/com/ericsson/gerrit/plugins/highavailability/Setup.java

diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Setup.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Setup.java
index 165b0dd..6635b80 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Setup.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Setup.java
@@ -105,9 +105,11 @@
     ui.message("\n");
     ui.header("%s Plugin", pluginName);
 
-    if (ui.yesno(true, "Configure %s", pluginName)) {
+    Path pluginConfigFile = site.etc_dir.resolve(pluginName + ".config");
+    boolean autoConfigure = !pluginConfigFile.toFile().exists();
+
+    if (ui.yesno(autoConfigure, "Configure %s", pluginName)) {
       ui.header("Configuring %s", pluginName);
-      Path pluginConfigFile = site.etc_dir.resolve(pluginName + ".config");
       config = new FileBasedConfig(pluginConfigFile.toFile(), FS.DETECTED);
       config.load();
       configureAutoReindexSection();