Create CaseSensitiveString to preserve case in header name

Create CaseSensitiveString (override the downcase and capitalize method to return self) and use it in the Http Request header to preserve the case in header name.
This is a workaround that Ruby library converts the header name (http://stackoverflow.com/questions/10258893/stop-ruby-http-request-modifying-header-name) while the OMS workflow is case sensitive.

source/code/plugins/oms_common.rb

@@ -729,4 +729,13 @@ def refresh_cache
 
   end
 
+  class CaseSensitiveString < String
+    def downcase
+        self
+    end
+    def capitalize
+        self
+    end
+  end
+
 end # module OMS

source/code/plugins/out_oms_blob.rb

@@ -70,7 +70,7 @@ def create_blob_get_request(uri)
     def create_blob_put_request(uri, msg)
       headers = {}
 
-      headers["x-ms-meta-timezoneid"] = OMS::Common.get_current_timezone
+      headers[OMS::CaseSensitiveString.new("x-ms-meta-timezoneid")] = OMS::Common.get_current_timezone
       headers["Content-Type"] = "application/octet-stream"
       headers["Content-Length"] = msg.bytesize.to_s