gpg: allow translation of more error messages

Mark these strings for translation so that error messages are
printed in the user's language of choice.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gpg-interface.c

@@ -109,10 +109,10 @@ int verify_signed_buffer(const char *payload, size_t payload_size,
 	args_gpg[0] = gpg_program;
 	fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
 	if (fd < 0)
-		return error("could not create temporary file '%s': %s",
+		return error(_("could not create temporary file '%s': %s"),
 			     path, strerror(errno));
 	if (write_in_full(fd, signature, signature_size) < 0)
-		return error("failed writing detached signature to '%s': %s",
+		return error(_("failed writing detached signature to '%s': %s"),
 			     path, strerror(errno));
 	close(fd);
 
@@ -124,7 +124,7 @@ int verify_signed_buffer(const char *payload, size_t payload_size,
 	args_gpg[2] = path;
 	if (start_command(&gpg)) {
 		unlink(path);
-		return error("could not run gpg.");
+		return error(_("could not run gpg."));
 	}
 
 	write_in_full(gpg.in, payload, payload_size);