package install (via runghc) does not complain when non-existing package version is used

[harendra-kumar]

The installer does not complain when a wrong version is specified. Instead when runghc tries to find the package-id using ghc-pkg it does not find it.

$ stack runghc --package text-9.9.9 version-conflict.hs
Run from outside a project, using implicit global project config
Using resolver: lts-6.7 from implicit global project's config file: /vol/hosts/cueball/.stack/global-project/stack.yaml
Could not find package id of package text-9.9.9