git-gui: drop msgfmt --statistics output

git-gui: drop msgfmt --statistics output

The catalog rules ran msgfmt with --statistics, whose output goes to
stderr and so survive "make -s".

The statistics are not needed, as in 2f12b31b746c (Makefile: don't
invoke msgfmt with --statistics, 2021-12-17). Remove it so a quiet
build stays quiet.

Signed-off-by: Harald Nordgren <redacted>
[j6t: adjust commit message]
Signed-off-by: Johannes Sixt <redacted>