tdb: 1.3.11 -> 1.3.15

Semi-automatic update. These checks were performed:

- built on NixOS
- ran `/nix/store/3dmmnilw4rsyrnz164vy04advblps0h5-tdb-1.3.15/bin/tdbdump -h` got 0 exit code
- ran `/nix/store/3dmmnilw4rsyrnz164vy04advblps0h5-tdb-1.3.15/bin/tdbbackup -h` got 0 exit code
- ran `/nix/store/3dmmnilw4rsyrnz164vy04advblps0h5-tdb-1.3.15/bin/tdbbackup --help` got 0 exit code
- ran `/nix/store/3dmmnilw4rsyrnz164vy04advblps0h5-tdb-1.3.15/bin/tdbbackup --help` and found version 1.3.15
- found 1.3.15 with grep in /nix/store/3dmmnilw4rsyrnz164vy04advblps0h5-tdb-1.3.15
- found 1.3.15 in filename of file in /nix/store/3dmmnilw4rsyrnz164vy04advblps0h5-tdb-1.3.15

cc "@wkennington"