Gem::Specification 中未定义方法“source”（NameError）

Question

我在使用 centos7 的服务器上部署应用程序时遇到问题。一切正常，capistrano 结束时没有错误，应用程序无法在乘客上运行。我收到错误

method `source' not defined in Gem::Specification (NameError)
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler/rubygems_ext.rb:17:in `remove_method'
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler/rubygems_ext.rb:17:in `<class:Specification>'
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler/rubygems_ext.rb:14:in `<module:Gem>'
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler/rubygems_ext.rb:13:in `<top (required)>'
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler.rb:10:in `require_relative'
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler.rb:10:in `<top (required)>'
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler/setup.rb:6:in `require_relative'
  /home/deploy/.rvm/gems/ruby-2.4.4/gems/bundler-2.1.4/lib/bundler/setup.rb:6:in `<top (required)>'
  /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require'
  /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require'
  /usr/share/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:361:in `activate_gem'
  /usr/share/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:221:in `block in run_load_path_setup_code'
  /usr/share/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:525:in `running_bundler'
  /usr/share/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:220:in `run_load_path_setup_code'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:91:in `preload_app'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:189:in `block in <module:App>'
  /usr/share/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:378:in `run_block_and_record_step_progress'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:188:in `<module:App>'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:30:in `<module:PhusionPassenger>'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:29:in `<main>'

在重新安装我的服务器之前，我遇到了同样的问题，但应用程序工作了几天，然后几天这个错误，并再次工作了几天，没有任何修复。