lxc: update obsolete void-specific config file

My lxc instances broke, these keys changed with 2.1

https://insights.ubuntu.com/2017/09/06/lxc-2-1-has-been-released/

srcpkgs/lxc/files/void.common.conf

@@ -2,13 +2,13 @@
 lxc.include = /usr/share/lxc/config/common.conf
 
 # Allow for 6 tty devices by default
-lxc.tty = 6
+lxc.tty.max = 6
 
 # Set the halt/stop signals
-lxc.haltsignal = SIGCONT
+lxc.signal.halt = SIGCONT
 
 # Uncomment to disable creating tty devices subdirectory in /dev
-lxc.devttydir =
+lxc.tty.dir =
 
 # Capabilities
 # Uncomment these if you don't run anything that needs the capability, and

srcpkgs/lxc/template

@@ -3,7 +3,7 @@ _desc="Linux Containers"
 
 pkgname=lxc
 version=2.1.1
-revision=2
+revision=3
 build_style=gnu-configure
 configure_args="--enable-doc --enable-seccomp --enable-cgmanager
  --enable-capabilities --disable-apparmor --with-distro=none