fixes directory glob inside jarfile with + in filename

when you have embedded gems inside a jarfile and the filename was something
like myjar-20150210+behappy.jar then the rubygems could not find those gems.

Sponsored by Lookout Inc.

Author: mkristian

core/src/main/java/org/jruby/util/JarResource.java

@@ -22,6 +22,8 @@ public static JarResource create(String pathname) {
         try {
             // since pathname is actually an uri we need to decode any url decoded characters like %20
             // which happens when directory names contain spaces
+            // but do not to decode '+' to allow '+' inside a filenames
+            sanitized = sanitized.replace("+", "%2B");
             sanitized = URLDecoder.decode(sanitized, "UTF-8");
         } catch (IllegalArgumentException iae) {
             // something in the path did not decode, so it's probably not a URI

test/jar_with+.jar

@@ -261,6 +261,13 @@ def test_loading_jar_with_leading_underscore
     }
   end
 
+  def test_jar_with_plus_in_name
+    assert_in_sub_runtime %{
+      require 'test/jar_with+.jar'
+      Dir['test/jar_with+.jar!/*'].size == 2
+    }
+  end
+
   # JRUBY-5045
   def test_cwd_plus_dotdot_jar_loading
     assert_equal "hi", run_in_sub_runtime(%{