build: Publish docs to correct rook.github.io repo

[travisn]

Description of your changes: Search and replace error when creating the nfs repo caused the docs publish to fail when retrieving a non-existent repo.

Checklist:

• [ ] Commit Message Formatting: Commit titles and messages follow guidelines in the developer guide.
• [ ] Skip Tests for Docs: Add the flag for skipping the build if this is only a documentation change. See here for the flag.
• [ ] Skip Unrelated Tests: Add a flag to run tests for a specific storage provider. See test options.
• [ ] Reviewed the developer guide on Submitting a Pull Request
• [ ] Documentation has been updated, if necessary.
• [ ] Unit tests have been added, if necessary.
• [ ] Integration tests have been added, if necessary.
• [ ] Pending release notes updated with breaking and/or notable changes, if necessary.
• [ ] Upgrade from previous release is tested and upgrade user guide is updated, if necessary.
• [ ] Code generation (make codegen) has been run to update object specifications, if necessary.