ci: integration: Set 'safe.directory' when installing QEMU from git

ci: integration: Set 'safe.directory' when installing QEMU from git

Since a fix for CVE-2022-24765 was released every git command is now
checked against the context repo in which it's supposed to run
resulting in a fatal error if the repo is owned by other user than the
one running the git command.
This means that in order to be able to do 'sudo make install', we have
to set the 'safe.directory' for the root user. This is because QEMU
runs 'git submodule update' automatically on 'make install'.

Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>