fixes #6607 / BZ 1106565 - Content View Package Filter Rules - allow duplicate name

Prior to this commit, a user could not create multiple package filter
rules for the same package (i.e. name) but different specific versions.

For example, if a repo had the following packages:
  package-0:1.0.0
  package-0:2.0.0
  package-0:3.0.0
  package-0:4.0.0

A user could not create rules to include/exclude the following packages:
  package-0:2.0.0
  package-0:4.0.0

With this commit, a user may now do that.  Name uniqueness will not apply when
the user has provided a version; however, it will, when the user has provided
min_version, max_version or if they have ommitted version.

For example,

The following would be valid,
  rule1 => name:package, version:2.0
  rule2 => name:package, version:4.0

The following would not be valid,
  rule1 => name:package, version:2.0
  --and--
  rule2 => name:package, max_version:0.1
  --or--
  rule2 => name:package, min_version:3.0
  --or--
  rule2 => name:package, version:"" (i.e. empty or not specified)