ceph_common.sh: fix typo in comment

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
mkcephfs.in: use mktemp instead of dd+md5sum+awk

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
mkcephfs.in: provide a valid rdir for MONs on -a

Provide also a valid rdir for ssh as in case of OSD/MDS hosts if
mkcephfs -a is called.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
mkcephfs.in: cleanup rdir in MON case

Remove $rdir in MON case of 'mkcephfs -a' as soon as it's no
longer needed.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
mkcephfs.in: use 32 chars for mktemp to be more unique

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #156 from dalgaaf/wip-da-fix-mkcephfs

Fix issues in mkcephfs

Reviewed-by: Sage Weil <sage@inktank.com>