check for boot files existence

releng/releng_isojigdo

@@ -153,7 +153,7 @@ CMD="${RELENG_XORRISO} \
 "
 
 # BOOT section
-if [ -f "${RELENG_ISOLINUX_BIN}" ]; then
+if [ -f "${RELENG_ISOLINUX_BIN}" -a -f "${ISOHYBRID_MBR}" -a -f "${APPEND_PART}" ]; then
 CMD+="\
  -b ${RELENG_ISOLINUX_BIN} \
  -c ${RELENG_BOOT_CAT} \
@@ -162,6 +162,8 @@ CMD+="\
  -partition_offset 16 \
  -append_partition 2 0x01 ${APPEND_PART} \
 "
+else
+ printf "\n${SELF}: FAIL to compose the boot section.\n"
 fi
 
 # JIGDO section