rubygems/util.rb: fix Gem::Util.popen

* lib/rubygems/util.rb (Gem::Util.popen): should close open pipe to
  reap the child process, in 1.9 or later.  fix deadlock on waiting
  the child process whose output is bigger than pipe buffer, in 1.8.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43724 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rubygems/util.rb

@@ -41,7 +41,7 @@ module Gem::Util
 
   def self.popen *command
     begin
-      r, = IO.popen command
+      r, = IO.popen command, &:read
     rescue TypeError # ruby 1.8 only supports string command
       r, w = IO.pipe
 
@@ -54,12 +54,13 @@ module Gem::Util
 
       w.close
 
+      begin
+        return r.read
+      ensure
         Process.wait pid
-
-      r
       end
-
-    r.read
+    end
+
   end
 
 end