init: ignore ret 8 from fsck if not force checking

when /flash or /storage is on non-persistent storage, it's not
yet available at the time fsck -a -p fires, so just skip
and force fsck only if ret=4

now, if /flash or /storage is non-persistent, users get
either non-recovered fs (just as it was before) or debug
shell if the fs is fubar (bad sb and so). nobody cares.

packages/sysutils/busybox/scripts/init

@@ -442,10 +442,7 @@
         FSCK_RET="$?"
 
         # FSCK_RET is the bit-wise OR of the exit codes for each filesystem that is checked.
-        if [ "$(( $FSCK_RET & 8 ))" = 8 ] ; then
-          # operational error
-          force_fsck
-        elif [ "$(( $FSCK_RET & 4 ))" = 4 ] ; then
+        if [ "$(( $FSCK_RET & 4 ))" = 4 ] ; then
           # errors left
           force_fsck
         elif [ "$(( $FSCK_RET & 2 ))" = 2 ] ; then