decompress_unxz: use common string

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/archival/libunarchive/decompress_unxz.c b/archival/libunarchive/decompress_unxz.c
index 800680f..5d7513a 100644
--- a/archival/libunarchive/decompress_unxz.c
+++ b/archival/libunarchive/decompress_unxz.c
@@ -92,7 +92,7 @@
 			break;
 		}
 		if (r != XZ_OK && r != XZ_UNSUPPORTED_CHECK) {
-			bb_error_msg("corrupted or unsupported data");
+			bb_error_msg("corrupted data");
 			total = -1;
 			break;
 		}