fix NoMethodError on ShellOut calls

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Error executing action `run` on resource 'execute[add repository]'
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NoMethodError
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undefined method `include?' for #<Mixlib::ShellOut:0x00000002c0b118>

Change-Id: Ib2f562e432373fe319eee1c8485cb112785b0f9b
Merge "fix NoMethodError on ShellOut calls"