Remove redundant key when updating test group document IDs
Remove redundant key when updating test group document IDs

The "kernel" key is already present in the initial spec to find the
job document so there's no need to update it again to search for a
build document.

Signed-off-by: Guillaume Tucker <e7e20b7c30f19d4ca6b81319ef81bf200369d137@collabora.com>

kernelci/kernelci-backend,kernelci/kernelci-backend