t/shelltest.od: quiet some error messages that get printed during testing.

If the error message only triggered a shelltest warning instead of a
failure, then they're harmless, so we might as well silence them when
running 'redo test' (which runs t/shelltest.do, which enables
SHELLTEST_QUIET).  We still want to print them when actually testing out
shelltest.od, though, to help with debugging the script.

t/shelltest.od

@@ -14,18 +14,30 @@
 #
 exec >&2
 set +e
+
 FAIL=
+
 fail()
 {
 	echo "  failed: $1"
 	FAIL=41
 }
+
 warn()
 {
 	echo "  warning: $1"
 	[ -n "$FAIL" ] || FAIL=42
 }
 
+quiet_stderr()
+{
+	if [ -n "$SHELLTEST_QUIET" ]; then
+		"$@" 2>/dev/null
+	else
+		"$@"
+	fi
+}
+
 
 name=foo.o.o
 ext=.o
@@ -69,7 +81,7 @@ t1=$(n 1 2 3 4 5 6 7 8 9 xx yy)
 
 
 chicken1=`echo " $spacey" | sed s/a/./g`
-chicken2="`echo " $spacey" | sed s/a/./g`"
+chicken2="`quiet_stderr echo " $spacey" | sed s/a/./g`"
 chicken3=$(echo " $spacey" | sed s/a/./g)
 chicken4="$(echo " $spacey" | sed s/a/./g)"
 [ "$chicken1" = " this h.s * .nd sp.ces" ] || fail 11
@@ -92,7 +104,7 @@ out=$(echo ${f1:-foo} ${f2:-foo} ${g1:=foo} ${g2:=foo})
 # quoting, which is apparently required by POSIX but not supported in some
 # shells.  But to make ash/dash not abort the test script *entirely* when it
 # fails, we use the $() + eval nonsense.
-f3=$(eval ': ${f3:=
+f3=$(quiet_stderr eval ': ${f3:=
 	a
 	b
 }' && echo "$f3")
@@ -176,10 +188,10 @@ c"
 # it check our syntax.
 #
 bob="a b *"
-bob=$(eval 'export bob=$bob:hello'; echo "$bob")
+bob=$(quiet_stderr eval 'export bob=$bob:hello'; echo "$bob")
 #[ "$bob" = "a b *:hello" ] || warn 46
 bob="a b *"
-nob=$(eval 'f() { local nob=$bob:hello; echo "$nob"; }'; f)
+nob=$(eval 'f() { local nob=$bob:hello; echo "$nob"; }'; quiet_stderr f)
 #[ "$nob" = "a b *:hello" ] || warn 47
 
 
@@ -334,7 +346,7 @@ rm -f || fail 110
 	HOME="$PWD/space home dir"
 	rm -rf "$HOME"
 	mkdir "$HOME"
-	cd ~ || exit 1
+	quiet_stderr cd ~ || exit 1
 	cd ..
 	rmdir 'space home dir'
 ) || warn 111