Merge Bundler 2.1.0.pre.1 as developed version from upstream.

a53709556b

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67539 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/bundler/yaml_serializer.rb

@@ -32,7 +32,7 @@ module Bundler
       (.*) # value
       \1 # matching closing quote
       $
-    /xo
+    /xo.freeze
 
     HASH_REGEX = /
       ^
@@ -40,12 +40,11 @@ module Bundler
       (.+) # key
       (?::(?=(?:\s|$))) # :  (without the lookahead the #key includes this when : is present in value)
       [ ]?
-      (?: !\s)? # optional exclamation mark found with ruby 1.9.3
       (['"]?) # optional opening quote
       (.*) # value
       \3 # matching closing quote
       $
-    /xo
+    /xo.freeze
 
     def load(str)
       res = {}