make sure to kill tail on exit
diff --git a/tools/build_lxc.sh b/tools/build_lxc.sh
index 42bd328..39046f0 100755
--- a/tools/build_lxc.sh
+++ b/tools/build_lxc.sh
@@ -282,6 +282,7 @@
     TAIL_PID=$!
 
     function kill_tail() {
+        kill $TAIL_PID
         exit 1
     }