[PATCH] intltool.m4: Properly align the ITMRG line emitted in a quiet build

The convention followed by other quiet build steps includes 2 spaces, a step identifier ("CC", "CCLD", "GEN", etc) left-aligned in a column of width 8, and a space. Match that convention so ITMRG lines line up with the rest of the quiet build output.

Here's an example of build output without this patch (with spaces replaced with underscores to make the lack of alignment visible, since Launchpad does not preserve whitespace):

__GPERF____src/login/logind-gperf.c
__CC_______src/login/user-sessions.o
__CC_______src/login/multi-seat-x.o
__GEN______units/emergency.service
__ITMRG__src/hostname/org.freedesktop.hostname1.policy
__ITMRG__src/locale/org.freedesktop.locale1.policy
__ITMRG__src/timedate/org.freedesktop.timedate1.policy
__ITMRG__src/login/org.freedesktop.login1.policy
__GEN______src/core/org.freedesktop.systemd1.policy.in
__GEN______src/core/macros.systemd
__M4_______units/getty@.service
__M4_______units/serial-getty@.service

Notice that the ITMRG lines don't line up with the rest.

I've attached a patch in bzr bundle format, applicable using:
bzr merge intltool-quiet-build-formatting.bzr.bundle