Remove dead getOldGitExe() code (#3936)

* Remove dead getOldGitExe() code and empty onLoaded() block

* remove onLoaded method

* Deprecate method instead of deleting it

Preserve API compatibility for consumers.  Low risk to delete it, but
it is simpler for maintainers if we retain the method rather than answer
later questions about its removal.

---------

Co-authored-by: Mark Waite <mark.earl.waite@gmail.com>

Author: meetgoti07

src/main/java/hudson/plugins/git/GitSCM.java

@@ -1811,10 +1811,12 @@ public void setAllowSecondFetch(boolean allowSecondFetch) {
         public void setAddGitTagAction(boolean addGitTagAction) { this.addGitTagAction = addGitTagAction; }
 
         /**
-         * Old configuration of git executable - exposed so that we can
-         * migrate this setting to GitTool without deprecation warnings.
-         * @return git executable
+         * Old configuration of git executable, unused since 2023.
+         * Returns null in all cases.
+         * @deprecated use GitTool
+         * @return null
          */
+        @Deprecated(since = "5.11.0")
         public String getOldGitExe() {
             return null;
         }
@@ -2166,21 +2168,6 @@ public boolean getDoGenerateSubmoduleConfigurations() {
         return doGenerateSubmoduleConfigurations;
     }
 
-    @Initializer(after=PLUGINS_STARTED)
-    public static void onLoaded() {
-        Jenkins jenkins = Jenkins.get();
-        DescriptorImpl desc = jenkins.getDescriptorByType(DescriptorImpl.class);
-
-        if (desc.getOldGitExe() != null) {
-            String exe = desc.getOldGitExe();
-            String defaultGit = GitTool.getDefaultInstallation().getGitExe();
-            if (exe.equals(defaultGit)) {
-                return;
-            }
-            System.err.println("[WARNING] you're using deprecated gitexe attribute to configure git plugin. Use Git installations");
-        }
-    }
-
     @Initializer(before=JOB_LOADED)
     public static void configureXtream() {
         Run.XSTREAM.registerConverter(new ObjectIdConverter());