[g5k-setup-docker] Add -p option to mkdirs

bin/g5k-setup-docker

@@ -17,8 +17,8 @@ def main
   ret = true
   ret &= sh('sudo-g5k').first if Process.euid != 0
   if options[:tmp]
-    ret &= sh('sudo mkdir /tmp/docker').first
-    ret &= sh('sudo mkdir /var/lib/docker').first
+    ret &= sh('sudo mkdir -p /tmp/docker').first
+    ret &= sh('sudo mkdir -p /var/lib/docker').first
     ret &= sh('sudo mount --bind /tmp/docker /var/lib/docker').first
   end
   cpu_arch = `uname -m`.strip