Fix portage provider to support version with character

[crigor]

I ran into an issue where chef 12 installs openssl 1.0.2d even if it's already installed. It doesn't support the character on the version, d.

According to man 5 ebuild

Versions are normally made up of two or three numbers separated by periods, such as 1.2 or 4.5.2. This string may be followed by a character such as 1.2a or 4.5.2z. Note that this letter is not meant to indicate alpha, beta, etc... status. For that, use the optional suffix; either _alpha, _beta, _pre (pre-release), _rc (release candidate), or _p (patch).

I added a test which failed before I added the fix. bundle exec rspec spec/unit/provider/package/portage_spec.rb shows passing tests.

This is my first PR on chef so let me know if I need to change anything.

[lamont-granquist]

@chef/client-core needs review

[lamont-granquist]

👍

[thommay]

👍

[smurawski]

👍