Use guard clause in Helm::InstallCommand

lib/gitlab/kubernetes/helm/install_command.rb

@@ -43,12 +43,12 @@ module Gitlab
         end
 
         def optional_tls_flags
-          if files.key?(:'ca.pem')
-            " --tls" \
-              " --tls-ca-cert #{files_dir}/ca.pem" \
-              " --tls-cert #{files_dir}/cert.pem" \
-              " --tls-key #{files_dir}/key.pem"
-          end
+          return unless files.key?(:'ca.pem')
+
+          " --tls" \
+            " --tls-ca-cert #{files_dir}/ca.pem" \
+            " --tls-cert #{files_dir}/cert.pem" \
+            " --tls-key #{files_dir}/key.pem"
         end
       end
     end