confile: support the network link string pattern matching

confile: support the network link string pattern matching

Enable lxc network config support the following type and link:

lxc.network.type = phys
lxc.network.link = eth+

Here, the suffix '+' will trigger a string pattern matching
and when lxc find any network interfaces name prefixed with
"eth" such as "eth0", "eth1", "ethxxxx" and so on, it will
try to move them into the container's namespace; If it didn't
find any matching, it would do nothing for this configure
line.

Signed-off-by: fli <fupan.li@windriver.com>