Log Message:
Fix problem raised by PR pkg/49313 by Ben Gergely,
if xdg-utils are installed already, grc_setup_freedesktop is installed.
(gnuradio-companion/Makefile)
(gnuradio-companion/PLIST)
 -  Add DEPENDS misc/xdg-utils
 -  Add REPLACE_BASH for above newly installed script
 -  Bump PKGREVISION

Related changes, problem was hidden if PKGREVISION was empty.
(gnuradio-core/Makefile.common) -> PLIST_SUBST
(gnuradio-core/Nocore.mk)       -> sed STRING
(gnuradio-core/PLIST)
  - shared library was suffixed as ${PKGVERSION}, but
    this should be ${PKGVERSION_NOREV} instead.
    Above files are affected.

(gnuradio-core/files/REPLACE_PYTHON)
  - Add one file
    grc/python/flow_graph.tmpl