myhsh: skip sisyphus_check if missed

bin/myhsh

@@ -106,8 +106,11 @@ fi
 
 # Skip checking for tar arg
 if [ -n "${LISTNAMES/*tar/}" ] ; then
-	$EPMCMD assure sisyphus_check || fatal
-	docmd sisyphus_check --no-check=$HASHER_NOCHECK --files $LISTNAMES || fatal "check for sisyphus failed"
+	if $EPMCMD assure sisyphus_check ; then
+		docmd sisyphus_check --no-check=$HASHER_NOCHECK --files $LISTNAMES || fatal
+	else
+		info "Skip sisyphus_check (no command is installed)"
+	fi
 fi
 
 # export OURAPTCONF with temp. file contains correct path to sources.list