redhat: nmsgtool/libnmsg path changes

the 'nmsgtool' path has changed:

    /usr/bin/nmsgtool -> /usr/lib{64,}/sie-dns-sensor/nmsgtool

the 'libnmsg' shared library and plugin has moved into a private library
directory:

    /usr/lib{64,}/ -> /usr/lib{64,}/sie-dns-sensor/

also, in the init script, rename /var/run/nmsgtool.pid to
/var/run/sie-dns-sensor.pid to match the package name.
build-deps/: update centos-5-amd64, centos-5-i386, centos-6-amd64, centos-6-i386 (rsync, wdns)

for all centos variants:
    update rsync from 3.0.9 to 3.1.0.
    update wdns from 0.4 to 0.5.
tarballs/nmsg-0.7.2.tar.gz: remove
tarballs/rsync_3.0.9.orig.tar.gz: remove
tarballs/wdns-0.4.tar.gz: remove
build-deps/: remove debian-6.0-amd64, debian-6.0-i386

these variants have been superseded by debian-7-amd64 and debian-7-i386.
debian: print post-installation support notice