mon: require name for 'auth add ...' command

Otherwise we interpret the empty string as 'unknown.'.

Fixes: #3956

Signed-off-by: Sage Weil <sage@inktank.com>
mds/Server.cc: fix warring assert.h's

New include boost/lexical_cast.hpp apparently drags in the system
assert.h on quantal and squeeze at least, breaking our careful
assert.h; re-include our file to fix it back

Fixes: #3957
Signed-off-by: Dan Mick <dan.mick@inktank.com>
Merge git://github.com/ceph/ceph