babeltrace: 1.5.3 -> 1.5.4

Semi-automatic update. The following tests were automatically performed:

- built on NixOS
- ran `/nix/store/kcq8gh0l8v2m71pyz5qqh8hiwnrfkwl6-babeltrace-1.5.4/bin/babeltrace -h` got 0 exit code
- ran `/nix/store/kcq8gh0l8v2m71pyz5qqh8hiwnrfkwl6-babeltrace-1.5.4/bin/babeltrace --help` got 0 exit code
- ran `/nix/store/kcq8gh0l8v2m71pyz5qqh8hiwnrfkwl6-babeltrace-1.5.4/bin/babeltrace -h` and found version 1.5.4
- ran `/nix/store/kcq8gh0l8v2m71pyz5qqh8hiwnrfkwl6-babeltrace-1.5.4/bin/babeltrace --help` and found version 1.5.4
- ran `/nix/store/kcq8gh0l8v2m71pyz5qqh8hiwnrfkwl6-babeltrace-1.5.4/bin/babeltrace-log -h` got 0 exit code
- ran `/nix/store/kcq8gh0l8v2m71pyz5qqh8hiwnrfkwl6-babeltrace-1.5.4/bin/babeltrace-log -h` and found version 1.5.4
- found 1.5.4 with grep in /nix/store/kcq8gh0l8v2m71pyz5qqh8hiwnrfkwl6-babeltrace-1.5.4