jenkins: workaround lfs bug

selfdrive/test/setup_device_ci.sh

@@ -55,15 +55,16 @@ cd $SOURCE_DIR
 
 rm -f .git/index.lock
 git reset --hard
-find . -maxdepth 1 -not -path './.git' -not -name '.' -not -name '..' -exec rm -rf '{}' \;
 git fetch --verbose origin $GIT_COMMIT
+find . -maxdepth 1 -not -path './.git' -not -name '.' -not -name '..' -exec rm -rf '{}' \;
 git reset --hard $GIT_COMMIT
 git checkout $GIT_COMMIT
 git clean -xdf
 git submodule update --init --recursive
 git submodule foreach --recursive "git reset --hard && git clean -xdf"
 
-git lfs prune
+git lfs pull
+(ulimit -n 65535 && git lfs prune)
 
 echo "git checkout done, t=$SECONDS"