configure: remove bogus LIBVIRT_GETTEXT macro reference

The LIBVIRT_GETTEXT macro was an artifact of patch development and
was later renamed to LIBVIRT_CHECK_NLS. This cruft causes configure
to print out

./configure: line 75084: LIBVIRT_GETTEXT: command not found

but fortunately this is non-fatal
Reported-by: NMartin Kletzander <mkletzan@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

configure.ac

@@ -734,8 +734,6 @@ if test "$enable_test_locking" = "yes"; then
 fi
 AM_CONDITIONAL([WITH_CIL],[test "$enable_test_locking" = "yes"])
 
-LIBVIRT_GETTEXT
-
 dnl Cygwin, MinGW and MSVC checks
 LIBVIRT_WIN_CHECK_COMMON
 LIBVIRT_WIN_CHECK_CYGWIN