After successful commit content from stdin is printed back

Here is the problematic scenario:
- run `git cz`
- enter data in prompts
- ghooks runs tests
- commit is created
- _everything what has bin printed after ghook started is printed again_

```
Iraklis-MacBook-Pro:free safareli$ git cz
cz-cli@2.8.2, cz-conventional-changelog@1.1.6

Line 1 will be cropped at 100 characters. All other lines will be wrapped after 100 characters.

? Select the type of change that you're committing: chore: Changes to the build process or auxiliary tools
and libraries such as documentation generation
? Denote the scope of this change ($location, $browser, $compile, etc.):
coverage
? Write a short, imperative tense description of the change:
add missing nyc to package.json
? Provide a longer description of the change:

? List any breaking changes or issues closed by this change:

> @safareli/free@0.0.0-placeholder check /Users/safareli/dev/shift/free
> npm run lint && npm run test

> @safareli/free@0.0.0-placeholder lint /Users/safareli/dev/shift/free
> eslint src test --ext js

> @safareli/free@0.0.0-placeholder test /Users/safareli/dev/shift/free
> nyc npm run test:pure

> @safareli/free@0.0.0-placeholder test:pure /Users/safareli/dev/shift/free
> cross-env NODE_ENV=test tape -r babel-core/register test/*.js

TAP version 13
# hoist
ok 1 should add 2 to all instructions in Free
# graft
ok 2 should graft other trees

1..2
# tests 2
# pass 2

# ok

----------|----------|----------|----------|----------|----------------|
File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
----------|----------|----------|----------|----------|----------------|
src/ | 65.08 | 50 | 48.78 | 66.67 | |
free.js | 65.08 | 50 | 48.78 | 66.67 |... 63,64,75,82 |
----------|----------|----------|----------|----------|----------------|
All files | 65.08 | 50 | 48.78 | 66.67 | |
----------|----------|----------|----------|----------|----------------|

[dev b8f4db2] chore(coverage): add missing nyc to package.json
1 file changed, 1 insertion(+)
[01:07:47] [dev b8f4db2] chore(coverage): add missing nyc to package.json
1 file changed, 1 insertion(+)

> @safareli/free@0.0.0-placeholder check /Users/safareli/dev/shift/free
> npm run lint && npm run test

> @safareli/free@0.0.0-placeholder lint /Users/safareli/dev/shift/free
> eslint src test --ext js

> @safareli/free@0.0.0-placeholder test /Users/safareli/dev/shift/free
> nyc npm run test:pure

> @safareli/free@0.0.0-placeholder test:pure /Users/safareli/dev/shift/free
> cross-env NODE_ENV=test tape -r babel-core/register test/*.js

TAP version 13
# hoist
ok 1 should add 2 to all instructions in Free
# graft
ok 2 should graft other trees

1..2
# tests 2
# pass 2

# ok

----------|----------|----------|----------|----------|----------------|
File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
----------|----------|----------|----------|----------|----------------|
src/ | 65.08 | 50 | 48.78 | 66.67 | |
free.js | 65.08 | 50 | 48.78 | 66.67 |... 63,64,75,82 |
----------|----------|----------|----------|----------|----------------|
All files | 65.08 | 50 | 48.78 | 66.67 | |
----------|----------|----------|----------|----------|----------------|
```

this output is from this [commit](https://github.com/safareli/free/commit/e6057962c145e4020d28e4c6c33b163bfdd353f5)

Riproduci il report con `git cz` e il flusso di test del commit-hook mostrato, quindi traccia come vengono gestiti stdin e l’output dell’hook dopo il completamento del commit. Verifica che i comandi di test e il loro output compaiano una sola volta dopo un commit riuscito, e aggiungi o esegui la coverage per questo scenario.

Scritto dal modello di indicizzazione a partire dal testo della issue.