(maint) RPM package provider broken on AIX.

Prior to this commit, the RPM package provider would barf when
attempting to run `self.instances` on AIX. The culprit is the archaic
version of RPM (3.0.5) on AIX. The RPM provider assumed that the
`--nodigest` option (introduced in 4.0.2, circa 2001) was available.
This commit removes the `--nodigest` option for RPM versions older than
4.0.2.
(AIX) Convert rpm comparisons (regex -> semver)

Prior to this commit, the RPM package provider was using regular
expressions for comparing versions of the `rpm` utility. The regex
method, while functional, is not exactly readable nor does the regex
hold up once `rpm` hits version 10. This commit uses SemVer (even though
the `rpm` versions are *semantically* versioned, the SemVer library
already exists and can easily handle version comparisons) for checking
the specific cases of `rpm` versions < 4.1 and < 4.0.2.

Sprintly: fixes item:195
(AIX) backport of master rpm_spec + fix for 2.7.x

This commit can, and should, be trashed when we merge the aix
integration branch into master.
(AIX) Add option tests for various crusty RPMs

Prior to this commit, we had no tests for the changing behaviour based
on version of RPM release. This commit add tests for magical old
versions of RPM, like that on AIX, 3.0.5 aka before the time began.

Sprintly: fixes item:195
(AIX) Change ternary to unless for old RPMs

Prior to this commit, the RPM package provider used a less readable
ternary operator for determining which flags to pass to `rpm`. This
commit alters each of those to be a simple suffixed `unless` condition.

This commit also includes the more correct `rpm --version` output which
contains a "\n", and the corresponding `strip` on the version number.
Merge pull request #1417 from jeffweiss/ticket/2.7.x/195_aix_hates_rpm_releases_that_arent_old_enough_to_drive

(AIX) RPM package provider broken on AIX.