mount/mount.ceph.c: remove unused variable

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
mds/Locker.cc: prefer prefix ++operator for iterators

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
test_short_dio_read.c: add proper error handling

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
qa/workunits/direct_io/test_sync_io.c: add proper error handling

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
client/Client.cc: handle error if _lookup() fails

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #123 from dalgaaf/wip-da-sca-misc-1

Some smaller misc fixes

Reviewed-by: Sage Weil <sage@inktank.com>