simpler check for od

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/applets/usage_compressed b/applets/usage_compressed
index 9436dcd..af66bc5 100755
--- a/applets/usage_compressed
+++ b/applets/usage_compressed
@@ -9,7 +9,8 @@
 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