(maint) Refactor hpux_spec.rb to reduce test redundancy

Prior to this commit tests for IP facts had significant duplication making it difficult to maintain in the event fixtures change or version support is added or dropped.

This commit consolidates the common features of the tests, making it easier to identify where maintenance should occur as fixtures change.
Merge pull request #467 from jhcarr/learning/master/noTicket-flayFacter

(maint) Refactor hpux_spec.rb to reduce test redundancy