Merge branch 'js/t5534-rev-parse-gives-multi-line-output-fix' into maint

A few tests that tried to verify the contents of push certificates
did not use 'git rev-parse' to formulate the line to look for in
the certificate correctly.

* js/t5534-rev-parse-gives-multi-line-output-fix:
t5534: fix misleading grep invocation

diff --cc t/t5534-push-signed.sh
Simple merge