simpler check for od

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

applets/usage_compressed

@@ -9,7 +9,8 @@ test -x "$loc/usage" || exit 1
 test "$SED" || SED=sed
 test "$DD" || DD=dd
 
-true | od -v -t x1 >/dev/null
+# Some people were bitten by their system lacking a (proper) od
+od -v -t x1 </dev/null >/dev/null
 if test $? != 0; then
 	echo 'od tool is not installed or cannot accept "-v -t x1" options'
 	exit 1