bisect.jpl: create a temporary unique tag for each build
bisect.jpl: create a temporary unique tag for each build

As configuration options and patches may be used in specific bisection
jobs, and to find boot jobs in LAVA for a given bisection, create a
temporary tag which will result in a unique git describe string.  This
way, each build and boot from bisection jobs is unique and not
confused with previous runs on the same bisection range.

Also remove any tag left behind by previously aborted jobs before
starting the bisection.  They can be found by searching for the
Jenkins job name.

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

kernelci/lava-ci-staging,kernelci/lava-ci-staging,kernelci/lava-ci-staging