[configure.ac] don't enable maintainer flags on even minor releases
[configure.ac] don't enable maintainer flags on even minor releases

pwithnall/mx,jonnylamb/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx,pwithnall/mx,clutter-project/mx,clutter-project/mx,pwithnall/mx,jonnylamb/mx,jonnylamb/mx,clutter-project/mx