lua: fix crash on missing blkio

Closes: #403
Signed-off-by: Dwight Engen
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

diff --git a/src/lua-lxc/lxc.lua b/src/lua-lxc/lxc.lua
index 44e4bf11ed3330e67956dc9c9b2a51f33d2e90a0..72a1531a807c875680c596b90d42217c0dde8fa1 100755 (executable)
--- a/src/lua-lxc/lxc.lua
+++ b/src/lua-lxc/lxc.lua
@@ -271,6 +271,10 @@ function container:stat_match_get_int(item, match, column)
     local val
     local lines = self:get_cgroup_item(item)
 
+    if (lines == nil) then
+       return 0
+    end
+
     for line in lines:gmatch("[^\r\n]+") do
        if (string.find(line, match)) then
            local col