utils: fix messages in ModuleManager

the error/warning messages were ill-formed for boost::fmt while checking the
compatibility of module versions vs. current VLE version.
utils: remove extra test of finished spawn

into get(string*, sting*) function, a test was performed on the spawn which
lead to the the fact that last log was not taken into account.
Merge branch 'vle-master'
Merge branch 'master' of https://github.com/Quentin-B/SDQI_VLE