add libmd.so.* to freebsd whitelist
add libmd.so.* to freebsd whitelist

the current version of this library seems to be the one in the freebsd
source code.  there's old versions that lack sha-2 support at

http://martin.hinner.info/libmd/
https://github.com/epowers/libmd

without something better to pull into as a software defn, it seems
best to just use the base o/s.

i also looked for ways of pointing the software at openssl instead of
libmd, but couldn't find any.

strangelittlemonkey/omnibus,szechyjs/omnibus,higanworks/omnibus,DataDog/omnibus-ruby,Altiscale/omnibus,jamesn/omnibus,strangelittlemonkey/omnibus,rapid7/omnibus,Scalr/omnibus,rapid7/omnibus,szechyjs/omnibus,chef/omnibus,chef/omnibus,chef/omnibus,higanworks/omnibus,Altiscale/omnibus,Scalr/omnibus,Altiscale/omnibus,Scalr/omnibus,szechyjs/omnibus,DataDog/omnibus-ruby,strangelittlemonkey/omnibus,jamesn/omnibus,jamesn/omnibus,DataDog/omnibus-ruby,rapid7/omnibus,higanworks/omnibus