Pass BUNDLE_PATH to install to the same path for test

lib/tasks/gitlab/gitaly.rake

@@ -21,7 +21,11 @@ namespace :gitlab do
       _, status = Gitlab::Popen.popen(%w[which gmake])
       command << (status.zero? ? 'gmake' : 'make')
 
-      command << 'BUNDLE_FLAGS=--no-deployment' if Rails.env.test?
+      if Rails.env.test?
+        command.push(
+          'BUNDLE_FLAGS=--no-deployment',
+          "BUNDLE_PATH=#{Bundler.bundle_path}")
+      end
 
       Gitlab::SetupHelper.create_gitaly_configuration(args.dir)
       Dir.chdir(args.dir) do

spec/tasks/gitlab/gitaly_rake_spec.rb

@@ -76,7 +76,11 @@ describe 'gitlab:gitaly namespace rake task' do
         end
 
         context 'when Rails.env is test' do
-          let(:command) { %w[make BUNDLE_FLAGS=--no-deployment] }
+          let(:command) do
+            %W[make
+               BUNDLE_FLAGS=--no-deployment
+               BUNDLE_PATH=#{Bundler.bundle_path}]
+          end
 
           before do
             allow(Rails.env).to receive(:test?).and_return(true)