cvc commit does not dereference recipe symlinks

[wfscheper]

Conary will not dereference symlink recipe file, but instead commits the symlink. Later attempts to update the source will cause the repository to return 500 Internal Server Errors.

Steps to reproduce:

1. Create a file foo.recipe.
2. Use cvc to create a new package foo
3. Create a symlink within the foo checkout to foo.recipe
4. Add and commit the symlinked recipe
5. Copy the real foo.recipe over the symlink and change the version
6. Commit the recipe

Conary will fail with a 500 ISE.

Workaround: if you use cvc remove to remove the recipe symlink and then use cvc add to add back a real file, then the commit will succeed.