[PATCH] Fix dependency for include/crfs-shared/rev.h Makefile target

[Zach Brown]

> A fresh hg clone of crfs resulted in a build error right out of
> the box.

Yeah, that was lame.  I fixed it by introducing a simple wire protocol
version number that we'll maintain instead of assuming that the user is
building in a hg repo and then going around digging in its internals..

  http://oss.oracle.com/mercurial/zab/crfs/rev/f4a298f141f8

Thanks for the report!

- z