Make tarsnap return same exit codes as bsdtar. Helps with detecting transient v fatal errors.

tar-write-exit-status.patch

--- tarsnap-autoconf-1.0.32.orig/tar/write.c    2012-02-22 13:10:53.000000000 +0100
+++ tarsnap-autoconf-1.0.32/tar/write.c 2012-06-28 02:10:21.000000000 +0200
@@ -683,7 +683,7 @@
 
        if (!tree) {
                bsdtar_warnc(bsdtar, errno, "%s: Cannot open", path);
-               bsdtar->return_value = 1;
+               bsdtar->return_value = 2;
                return;
        }
 
@@ -709,7 +709,7 @@
                if (tree_ret == TREE_ERROR_DIR) {
                        bsdtar_warnc(bsdtar, errno,
                            "%s: Couldn't visit directory", name);
-                       bsdtar->return_value = 1;
+                       bsdtar->return_value = 3;
                }
                if (tree_ret != TREE_REGULAR)
                        continue;
@@ -729,7 +729,7 @@
                        /* Couldn't lstat(); must not exist. */
                        bsdtar_warnc(bsdtar, errno, "%s: Cannot stat", name);
                        /* Return error if files disappear during traverse. */
-                       bsdtar->return_value = 1;
+                       bsdtar->return_value = 4;
                        continue;
                }