Output errors of "composer create-project" command

[mbrodala]

Instead of swallowing all errors by running composer create-project as test command, do this normally and declare that it creates a composer.json which can be expected as a result of this command.

This has the big advantage that all kind of errors are now shown by Puppet.

[mbrodala]

@igalic Do you think you can make a new release with this fix?

[igalic]

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665 examples, 0 failures

i think we need one more test.

[mbrodala]

Not sure what you mean exactly. You mean a test which covers the error case?

[igalic]

@mbrodala nah, one more test, so we get 666 xD