Don't add a file to revtree if we didn't add it to tree

Dependencies

• [2] CCLLB7OI Upgrading to Sanakirja 0.15 + version bump
• [3] YN63NUZO Sanakirja 1.0
• [4] 5BRU2RRW Cleanup (debugging a crash related to trees/inodes)
• [5] I52XSRUH Massive cleanup, and simplification
• [6] VO5OQW4W Removing anyhow in libpijul
• [*] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).

Change contents

• replacement in libpijul/src/pristine/mod.rs at line 1606
  [3.19085]→[3.1980:2053](∅→∅),[2.75255]→[3.1980:2053](∅→∅),[3.1980]→[3.1980:2053](∅→∅)
  − txn.put_tree(file_id, inode)?;

  − txn.put_revtree(inode, file_id)?;
  [2.75255]

  [3.50319]
  + if txn.put_tree(file_id, inode)? {

  + txn.put_revtree(inode, file_id)?;

  + }