Fix the exception message shown when there's an IOError

while closing a socket in the pool.

lib/mongo/util/pool.rb

@@ -49,8 +49,7 @@ module Mongo
         begin
           sock.close
         rescue IOError => ex
-          warn "IOError when attempting to close socket connected "
+          warn "IOError when attempting to close socket connected to #{@host}:#{@port}: #{ex.inspect}"
-           + "to #{@host}:#{@port}: #{ex.inspect}"
         end
       end
       @host = @port = nil

test/connection_test.rb

@@ -264,5 +264,15 @@ class TestConnection < Test::Unit::TestCase
       end
       assert_equal 0, @con.primary_pool.checked_out.size
     end
+
+    should "show a proper exception message if an IOError is raised while closing a socket" do
+      fake_socket = Mocha::Mock.new
+      fake_socket.stubs(:close).raises(IOError.new)
+      fake_socket.stub_everything
+      TCPSocket.expects(:new).returns(fake_socket)
+
+      @con.primary_pool.checkout_new_socket
+      assert_equal [], @con.primary_pool.close
+    end
   end
 end