Fix current contribution flow

[nodo]

The current flow for contributions if the following:

1. Fork ginkgo
2. Install gomega
3. cd $GOPATH/src/github.com/USERNAME && git clone git@github.com:USERNAME/ginkgo.git
4. AWESOME CODING
5. ./before_pr.sh
6. Run ginkgo -r
7. Open a PR if tests are all green

However, when running the tests I see:

Summarizing 1 Failure:

[Fail] Coverage Specs when it runs coverage analysis in series and in parallel [It] works
/Users/andreanodari/go/src/github.com/nodo/ginkgo/integration/coverage_test.go:23

Ran 119 of 119 Specs in 262.852 seconds

And in particular the tests fails because the coverage is not correct:

Got stuck at:
      Running Suite: CoverageFixture Suite
      ====================================
      Random Seed: 1530691030
      Will run 5 of 5 specs

      •••••
      Ran 5 of 5 Specs in 0.000 seconds
      SUCCESS! -- 5 Passed | 0 Failed | 0 Pending | 0 Skipped
      PASS
      coverage: 0.0% of statements

      Ginkgo ran 1 suite in 1.39062547s
      Test Suite Passed

  Waiting for:
      coverage: 80.0% of statements

I think this happens because the fixtures and the tests are not properly changed by the script (see for instance these imports).

[nodo]

See #494 (comment)

[nodo]

Fixed in #494