git: update to v2.22.0

Update to git version v2.22.0.

Upstream commit bce9db6d ("trace2: use system/global config for default
trace2 settings") caused a regression. We have to unset HOME and
XDG_CONFIG_HOME before early loading of config from trace2 code kicks in.

Signed-off-by: Christian Hesse <mail@eworm.de>
3 files changed