[C++][CI] Fuzzit does not know about branch + commit hash

[asfimport]

Reported here, fuzzit does not seem to retrieve the branch + commit hash, which is bad for tracking.

AC

• Fix CI setup (hint)
• Use set -euxo pipefail in `docker_build_and_fuzzit.sh` to prevent this issue in the future

Reporter: Marco Neumann / @crepererum
Assignee: Marco Neumann / @crepererum

PRs and other links:

• GitHub Pull Request #4952

_{Note: This issue was originally created as ARROW-5959. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 4952
#4952