change parameter ordering for rpmbuild, fixes ignoring arch on OSX

On OSX strict parameter ordering is required for rpmbuild. This results in x86_64 rpms when noarch is specified in the build, for example. We recently noted this issue in the similar maven packager with fix here https://github.com/rickard-von-essen/rpm-maven-plugin/commit/673e61e432aeef1229bcb040b6db9cf8f9239b38 and SO post noting it here http://stackoverflow.com/questions/8051744/macosx-rpmbuild-target-noarch-doesnt-work