bsdinstall and current (possible stable) snapshots

Hi Devin,

Recently I'm trying to install FreeBSD CURRENT from bootonly image
( FreeBSD-11.0-CURRENT-amd64-20150302-r279514-bootonly.iso)
on IBM HS22 blade via bladecenter's kvm but I faced with problem on checksum
stage, bootonly doesn't contain base, kernel,etc distributions but it contain
manifest file. 
On mirrors we have  pub/FreeBSD/snapshots/${ARCH}/11.0-CURRENT/*txz and
MANIFEST, sha256 sums from _local_ manifest doesn't match sha256 sums for
fetched files. I suppose it will be fine with RELEASE bootonly iso but not with
stable/current.
there is 2 ways how we can handle it:
1) download remote MANIFEST if spotted checksum mismatch and trying to use it
2) allow user to continue installation with 'broken' distributions 

I had to first put 10.1 then update it to HEAD :(

What do you think ?

--
wbr, tiger