When the Project has LFS enabled, we try to lock the file through the
LFS locking feature too, given we can only lock files through LFS, this
operation was raising an error.

Additionally a couple of errors has been fixed:

- The previous implementation was only looking for LFS files in the root
  of the project given `@path` was `nil`
- We were trying to create the PathLock record twice, it was silently
  failing due to the usage of `create` instead of `create!`