qemu: Use 'ar' instead of '7z'

7z is unnecessary since the simpler ar is sufficient.
7z sometimes seems to fail locally for unknown reason.

Test: test locally
Change-Id: If064a527bdee9253b7d22b574216356dba94c1a9

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/buildbot-vm.sh b/tools/buildbot-vm.sh
index e6edd0b247..356b781a3e 100755
--- a/tools/buildbot-vm.sh
+++ b/tools/buildbot-vm.sh
@@ -32,7 +32,7 @@ action="$1"
 get_stable_binary() {
     mkdir tmp && cd tmp
     wget "http://security.ubuntu.com/ubuntu/pool/main/$1"
-    7z x "$(basename $1)" && zstd -d data.tar.zst && tar -xf data.tar
+    ar x "$(basename $1)" && zstd -d data.tar.zst && tar -xf data.tar
     mv "$2" ..
     cd .. && rm -rf tmp
 }