Fix connection reset error

[sergicastro]

Starting mock server
Run options: 
# Running tests:
..E.......
Finished tests in 0.026575s, 376.2927 tests/s, 451.5512 assertions/s.
  1) Error:
test_add(ManageCredentialsOKTest):
Errno::ECONNRESET: Connection reset by peer
    /home/travis/build/sergicastro/manage-credentials/lib/api_client.rb:21:in `send_request'
    /home/travis/build/sergicastro/manage-credentials/lib/api_client.rb:68:in `post_credentials'
    /home/travis/build/sergicastro/manage-credentials/lib/business_service.rb:18:in `add'
    /home/travis/build/sergicastro/manage-credentials/lib/manage_credentials.rb:14:in `add'
    /home/travis/.rvm/gems/ruby-1.9.3-p551/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
    /home/travis/.rvm/gems/ruby-1.9.3-p551/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
    /home/travis/.rvm/gems/ruby-1.9.3-p551/gems/thor-0.19.1/lib/thor.rb:359:in `dispatch'
    /home/travis/.rvm/gems/ruby-1.9.3-p551/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
    /home/travis/build/sergicastro/manage-credentials/test/test_managecredentials_ok.rb:111:in `test_add'
10 tests, 12 assertions, 0 failures, 1 errors, 0 skips
rake aborted!
Command failed with status (1): [ruby -I"lib:test" -I"/home/travis/.rvm/gems/ruby-1.9.3-p551/gems/rake-10.5.0/lib" "/home/travis/.rvm/gems/ruby-1.9.3-p551/gems/rake-10.5.0/lib/rake/rake_test_loader.rb" "test/test_helper.rb" "test/test_managecredentials_error.rb" "test/test_managecredentials_ok.rb" ]
/home/travis/.rvm/gems/ruby-1.9.3-p551/bin/ruby_executable_hooks:15:in `eval'
/home/travis/.rvm/gems/ruby-1.9.3-p551/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => default => test
(See full trace by running task with --trace)