This fixes the dirty checkouts for me.

When I freshly clone monotouch-bindings, my master branch is in a really strange state– `PayPalMobileExpressCheckout /*` files are marked as deleted but not added, and `PayPalMobileExpressCheckout` is shown as untracked:

```shell
$ git clone git@github.com:mono/monotouch-bindings.git
$ cd monotouch-bindings
$ git st -s
 D "PayPalMobileExpressCheckout /Makefile"
 D "PayPalMobileExpressCheckout /binding/.gitignore"
 D "PayPalMobileExpressCheckout /binding/AssemblyInfo.cs"
 D "PayPalMobileExpressCheckout /binding/Makefile"
 D "PayPalMobileExpressCheckout /binding/enums.cs"
 D "PayPalMobileExpressCheckout /binding/paypal.cs"
 D "PayPalMobileExpressCheckout /docs/MonoTouch.PayPal/DeviceReferenceTokenDelegate.xml"
 D "PayPalMobileExpressCheckout /docs/MonoTouch.PayPal/PayPal.xml"
 D "PayPalMobileExpressCheckout /docs/MonoTouch.PayPal/PayPalButtonType.xml"
 D "PayPalMobileExpressCheckout /docs/MonoTouch.PayPal/PayPalEnvironment.xml"
 D "PayPalMobileExpressCheckout /docs/index.xml"
 D "PayPalMobileExpressCheckout /docs/ns-MonoTouch.PayPal.xml"
 D "PayPalMobileExpressCheckout /docs/ns-paypal.xml"
 D "PayPalMobileExpressCheckout /docs/paypal/Messaging.xml"
?? PayPalMobileExpressCheckout/
```

This commit fixes this strange state, but I didn't commit to master because I have no clue what's going on. I've tried this with multiple versions of git and fresh clones are always dirty. Alan tried to reproduce the behavior but could not.