Don't warn when deinit'ing submodules

bundler/lib/bundler/source/git/git_proxy.rb

@@ -136,7 +136,9 @@ def copy_to(destination, submodules = false)
           if submodules
             git_retry "submodule update --init --recursive", :dir => destination
           elsif Gem::Version.create(version) >= Gem::Version.create("2.9.0")
-            git_retry "submodule deinit --all --force", :dir => destination
+            inner_command = "git -C $toplevel submodule deinit --force $sm_path"
+            inner_command = inner_command.gsub("$") { '\$' } unless Bundler::WINDOWS
+            git_retry "submodule foreach --quiet \"#{inner_command}\"", :dir => destination
           end
         end
 

bundler/spec/install/gemfile/git_spec.rb

@@ -864,6 +864,24 @@
     expect(the_bundle).to include_gems "has_submodule 1.0"
   end
 
+  it "does not warn when deiniting submodules" do
+    build_git "submodule", "1.0"
+    build_git "has_submodule", "1.0"
+
+    sys_exec "git submodule add #{lib_path("submodule-1.0")} submodule-1.0", :dir => lib_path("has_submodule-1.0")
+    sys_exec "git commit -m \"submodulator\"", :dir => lib_path("has_submodule-1.0")
+
+    install_gemfile <<-G
+      git "#{lib_path("has_submodule-1.0")}" do
+        gem "has_submodule"
+      end
+    G
+    expect(err).to be_empty
+
+    expect(the_bundle).to include_gems "has_submodule 1.0"
+    expect(the_bundle).to_not include_gems "submodule 1.0"
+  end
+
   it "handles implicit updates when modifying the source info" do
     git = build_git "foo"