Update VersionManagement.js

[jonaswindey]

trafficstars

Add error code when command fails

[Unitech]

@jonaswindey would you mind to do this PR again on PM2 v2: https://github.com/Unitech/pm2/blob/79ba743723131436bd049cc952e2b1f1158bc84c/lib/tools/VersionManagement.js#L294

thanks

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