libtool: do not link lxcfs against liblxcfs

libtool: do not link lxcfs against liblxcfs

Make liblxcfs a libtool module. Also, stop linking lxcfs against liblxcfs. We do
not really need this since we call dlopen() anyway. Furthermore, this allows us
to make sure that functions marked with __attribute__(constructor) are not run
before we call dlopen() in main() in lxcfs. This has the advantage that we can
show help output without __attribute__(constructor) functions being run.

Signed-off-by: Christian Brauner <cbrauner@suse.de>