Merge branch 'blackst0ne-rails5-fix-gitlab-ci-trace-stream-delegate-valid' into 'master'

[Rails5] Remove `as` keyword from `Gitlab:Ci:Trace:Stream.delegate :valid?`

See merge request gitlab-org/gitlab-ce!18270

lib/gitlab/ci/trace/stream.rb

@@ -10,7 +10,9 @@ module Gitlab
 
         delegate :close, :tell, :seek, :size, :url, :truncate, to: :stream, allow_nil: true
 
-        delegate :valid?, to: :stream, as: :present?, allow_nil: true
+        delegate :valid?, to: :stream, allow_nil: true
+
+        alias_method :present?, :valid?
 
         def initialize
           @stream = yield