src/pmns/Rebuild: use fullpath for pmnsmerge
src/pmns/Rebuild: use fullpath for pmnsmerge

1. be consistent within the script
2. needed for Windows port

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp