Remove duplicate VersionInfo class

This was brought over during the CI merge and already exists at
`lib/gitlab/version_info.rb`.

lib/ci/version_info.rb

@@ -1,52 +0,0 @@
-class VersionInfo
-  include Comparable
-
-  attr_reader :major, :minor, :patch
-
-  def self.parse(str)
-    if str && m = str.match(/(\d+)\.(\d+)\.(\d+)/)
-      VersionInfo.new(m[1].to_i, m[2].to_i, m[3].to_i)
-    else
-      VersionInfo.new
-    end
-  end
-
-  def initialize(major = 0, minor = 0, patch = 0)
-    @major = major
-    @minor = minor
-    @patch = patch
-  end
-
-  def <=>(other)
-    return unless other.is_a? VersionInfo
-    return unless valid? && other.valid?
-
-    if other.major < @major
-      1
-    elsif @major < other.major
-      -1
-    elsif other.minor < @minor
-      1
-    elsif @minor < other.minor
-      -1
-    elsif other.patch < @patch
-      1
-    elsif @patch < other.patch
-      -1
-    else
-      0
-    end
-  end
-
-  def to_s
-    if valid?
-      "%d.%d.%d" % [@major, @minor, @patch]
-    else
-      "Unknown"
-    end
-  end
-
-  def valid?
-    @major >= 0 && @minor >= 0 && @patch >= 0 && @major + @minor + @patch > 0
-  end
-end