Fix generating SSH key fingerprints with OpenSSH 6.8.

Replaces https://github.com/gitlabhq/gitlabhq/pull/9008.

Fixes gitlab-org/gitlab-ce#1289.

cc @jacobvosmaer

app/models/key.rb

@@ -16,7 +16,6 @@ require 'digest/md5'
class Key < ActiveRecord::Base
include Sortable
-  include Gitlab::Popen
belongs_to :user
@@ -79,20 +78,9 @@ class Key < ActiveRecord::Base
def generate_fingerprint
self.fingerprint = nil
-    return unless key.present?
-
-    cmd_status = 0
-    cmd_output = ''
-    Tempfile.open('gitlab_key_file') do |file|
-      file.puts key
-      file.rewind
-      cmd_output, cmd_status = popen(%W(ssh-keygen -lf #{file.path}), '/tmp')
-    end
-
-    if cmd_status.zero?
-      cmd_output.gsub /(\h{2}:)+\h{2}/ do |match|
-        self.fingerprint = match
-      end
-    end
+
+    return unless self.key.present?
+
+    self.fingerprint = Gitlab::KeyFingerprint.new(self.key).fingerprint
end
end