mountd: support IPv6 [] escaping with fsloc hosts

mountd: support IPv6 [] escaping with fsloc hosts

mountd uses colons to split fsloc hosts, but this doesn't work with IPv6
addresses (they contain ':').

To fix this, mountd is changed to expect all IPv6 addresses to be escaped
by '[' and ']' so colons that are part of the address may be skipped.
To fix IPv6 referrals, this patch must be used with the nfsd patch that
properly parses escaped IPv6 addresses in fs_location->hosts.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Steve Dickson <steved@redhat.com>