Clean up "Cloning into 'submodule-1.0'..." output messages from test suite

- Removes the following output messages from the test suite:
```
Cloning into 'submodule-1.0'...
done.
```

1 files changed, 3 insertions, 3 deletions

diff --git a/spec/install/gemfile/git_spec.rb b/spec/install/gemfile/git_spec.rb
index ec4bd59e..ec148f99 100644
--- a/spec/install/gemfile/git_spec.rb
+++ b/spec/install/gemfile/git_spec.rb
@@ -575,7 +575,7 @@ describe "bundle install with git sources" do
       s.add_dependency "submodule"
     end
     Dir.chdir(lib_path("has_submodule-1.0")) do
-      `git submodule add #{lib_path("submodule-1.0")} submodule-1.0`
+      sys_exec "git submodule add #{lib_path("submodule-1.0")} submodule-1.0", :expect_err => true
       `git commit -m "submodulator"`
     end
 
@@ -595,11 +595,11 @@ describe "bundle install with git sources" do
       s.add_dependency "submodule"
     end
     Dir.chdir(lib_path("has_submodule-1.0")) do
-      `git submodule add #{lib_path("submodule-1.0")} submodule-1.0`
+      sys_exec "git submodule add #{lib_path("submodule-1.0")} submodule-1.0", :expect_err => true
       `git commit -m "submodulator"`
     end
 
-    install_gemfile <<-G
+    install_gemfile <<-G, :expect_err => true
       git "#{lib_path("has_submodule-1.0")}", :submodules => true do
         gem "has_submodule"
       end