Fix the variable substitution

Prior to that commit if ceph_version was equal to 0.80.5, the variable
substitution ${ceph_version%.*} was returning 0.80 and not 0. Using
${ceph_version%%.*} returns the desired value.
Also refactoring the version output to get a X.X format since only
major and minor are important.

Change-Id: Iab50f3c4b24a01a68acda417eae0501f00038f54
Signed-off-by: Sébastien Han <sebastien.han@enovance.com>
Merge "Fix the variable substitution"