Use array access, and remove unnecessary double `error` from array lookup#25

Merged

jsor merged 2 commits intoreactphp:masterfrom

WyriHaximus-labs:handle-child-process-error

Jun 18, 2018

Commits on May 28, 2018

Get the error from the child process in the correct way
WyriHaximus
committed

Commits on Jun 15, 2018

Test the error coming from the pool is pickup and passed up through the promises to the callee, via @clue at https://github.com/reactphp/filesystem/pull/25#discussion_r191571410
WyriHaximus
committed