net: Read bracketed IPv6 addrs and port numbers

net: Read bracketed IPv6 addrs and port numbers

Allow specifying port numbers for http and tftp paths and allow IPv6
addresses to be recognized with brackets around them, which is required
to specify a port number.

Co-authored-by: Aaron Miller <aaronmiller@fb.com>
Signed-off-by: Aaron Miller <aaronmiller@fb.com>
Co-authored-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>