build: osx: Fix incomplete framework packaging for codesigning

Starting with 10.9, Framework versions must be signed individually, rather
than as a single bundle version, in order to be properly codesigned. This
change ensures that the proper plist files and symlinks are present prior to
packaging.

I believe I've tested this on all of my build scenarios, including the future static qt.

@gavinandresen Please give this a real-world try (preferably by merging it into -rc1 locally and signing a gitian build there as though it were rc2) before ACKing. It worksforme (tm), but that means very little for Apple's tools.

Also, note that --deep will be needed for codesign until we switch to static libs.