Fix cannot find version of process

[KSH-code]

• The error occurs that is because process of execjs has been removed from rails/execjs@b0be19c
• use shell script instead of execjs eval to fix it.
• Fix TypeError: Cannot read property 'version' of undefined #203

[KSH-code]

Ooops, it was solved by 3b3d244

is this pr not needed? @albb0920
If no, I will close.

[albb0920]

Thanks for the PR,
but I don't think dropping MiniRacer support is desirable at this point,
if people are using it without troubles, I'd like to avoid breaking changes.

So I've drop the version check as I mentioned in #203, sorry for the delay, I'll publish a new version shortly.
3b3d244

[KSH-code]

Yup, I agree that.
Thanks for check.