nhc: Fix detached mode result writability test

In detached mode, we check to see if we can write to the result file
before actually trying to do so, but `test -w` returns false for
non-existent files, not just unwritable files.  So we need to redo the
logic of that test to account for both cases: (1) file exists and is
writable, or (2) file does not exist but directory does and is
writable.

While I was at it, I also changed where the write is done to account
for a third scenario:  (3) everything looks like it should work but
the write itself fails.

Fixes #59.  Thanks to @hwj0303 for spotting this!

Author: mej

nhc

@@ -61,11 +61,11 @@ function die() {
         fi
     fi
     if [[ -n "$NHC_DETACHED" ]]; then
-        if [[ -w "$RESULTFILE" ]]; then
-            echo "$RET $*" > $RESULTFILE
+        if [[ -w "$RESULTFILE" || (! -e "$RESULTFILE" && -w "${RESULTFILE%/*}") ]] && echo "$RET $*" > $RESULTFILE ; then
+            dbg "Wrote results file $RESULTFILE:  $RET $*"
         else
-            log "ERROR:  $NAME:  Unable to write to \"$RESULTFILE\" -- is ${RESULTFILE%/*} read-only?"
-            syslog "ERROR:  $NAME:  Unable to write to \"$RESULTFILE\" -- is ${RESULTFILE%/*} read-only?"
+            log "ERROR:  $NAME:  Unable to write to \"$RESULTFILE\" -- is ${RESULTFILE%/*} missing/read-only?"
+            syslog "ERROR:  $NAME:  Unable to write to \"$RESULTFILE\" -- is ${RESULTFILE%/*} missing/read-only?"
             syslog_flush
         fi
     elif [[ "$NHC_RM" == "sge" ]]; then