tracker: add PACKAGECONFIG for nautilus extension

* fixes following floating dependencies:
  WARN: tracker: tracker-nautilus-extension rdepends on atk, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on cairo, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on eglibc, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on expat, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on fontconfig, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on freetype, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on gdk-pixbuf, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on glib-2.0, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on gtk+, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on harfbuzz, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libffi, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libpng, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libsqlite3, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libunistring, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libx11, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libxau, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libxcb, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libxcb-render, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libxcb-shm, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libxdmcp, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libxext, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on libxrender, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on pango, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on pixman, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on tracker, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on util-linux-libuuid, but it isn't a build dependency?
  WARN: tracker: tracker-nautilus-extension rdepends on zlib, but it isn't a build dependency?

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>