debian: Add intltoolize to dh_auto_configure

debian: Add intltoolize to dh_auto_configure

Debian has automated building tools that handle source trees directly.
It is expected that you can pick up a source tarball, and with the
appropriate debian/ subtree, a successful build can be produced using
the `debuild` tool. This depends on all the build steps having been
included as part of the debian/rules file (see: `man debuild`).

This commit ensures there is no need to manually run autogen.sh
on a locally extracted source tarball prior to building for Debian.
This is accomplished by adding the `intltoolize` command to the
override_dh_auto_configure step in d/rules.

There is no need to add the `autoreconf` command due to dh-autoreconf
always handling that prior to the dh_auto_configure step.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>