MFH (r254407, r254960, r255371): misc cleanup
MFH (r255386): make libssh private
MFH (r255369, r255376, r255393, r262530): import OpenPAM Nummularia
MFH (r255590): list OpenSSH in OptionalObsoleteFiles.inc
Also fix the libssh-went-private bit in ObsoleteFiles.inc, which was
incomplete.