Git::I18N: compatibility with perl <5.8.3

Change the Exporter invocation in Git::I18N to be compatible with
5.8.0 to 5.8.2 inclusive. Before Exporter 5.57 (released with 5.8.3)
Exporter didn't export the 'import' subroutine.

Reported-by: Tom G. Christensen <tgc@statsbiblioteket.dk>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

perl/Git/I18N.pm

@@ -2,7 +2,16 @@ package Git::I18N;
 use 5.008;
 use strict;
 use warnings;
-use Exporter 'import';
+BEGIN {
+	require Exporter;
+	if ($] < 5.008003) {
+		*import = \&Exporter::import;
+	} else {
+		# Exporter 5.57 which supports this invocation was
+		# released with perl 5.8.3
+		Exporter->import('import');
+	}
+}
 
 our @EXPORT = qw(__);
 our @EXPORT_OK = @EXPORT;