Update the keys permission check to open the file in write mode.

That way the file is created if it does not exist.

lib/gitlab_keys.rb

@@ -106,7 +106,7 @@ class GitlabKeys
   end
 
   def check_permissions
-    open_auth_file('r+') { true }
+    open_auth_file(File::RDWR | File::CREAT) { true }
   rescue => ex
     puts "error: could not open #{auth_file}: #{ex}"
     if File.exist?(auth_file)

spec/gitlab_keys_spec.rb

@@ -183,6 +183,13 @@ describe GitlabKeys do
       gitlab_keys.should_receive(:open_auth_file).and_raise("imaginary error")
       expect(gitlab_keys.exec).to eq(false)
     end
+
+    it 'creates the keys file if it does not exist' do
+      create_authorized_keys_fixture
+      FileUtils.rm(tmp_authorized_keys_path)
+      expect(gitlab_keys.exec).to eq(true)
+      expect(File.exist?(tmp_authorized_keys_path)).to eq(true)
+    end
   end
 
   describe :exec do