Add more variables for the splash.svg image (Closes: 1015782)

The request asked for 5 additional variables to be resolved for the SVG
images:
Added: LB_ISO_APPLICATION, LB_ISO_PUBLISHER and LB_LINUX_PACKAGES
Not added: LB_ISO_PREPARER: xorriso recommends not changing this
variable
Not added: LB_ISO_VOLUME: is can contain '@ISOVOLUME_TS@' which resolves
to a timestamp and would need additional handling

scripts/build/binary_syslinux

@@ -261,6 +261,9 @@ do
 			-e "s|@LIVE_BOOT_VERSION@|${_LIVE_BOOT_VERSION}|g" \
 			-e "s|@LIVE_CONFIG_VERSION@|${_LIVE_CONFIG_VERSION}|g" \
 			-e "s|@LIVE_TOOLS_VERSION@|${_LIVE_TOOLS_VERSION}|g" \
+			-e "s|@LB_ISO_APPLICATION@|${LB_ISO_APPLICATION}|g" \
+			-e "s|@LB_ISO_PUBLISHER@|${LB_ISO_PUBLISHER}|g" \
+			-e "s|@LB_LINUX_PACKAGES@|${LB_LINUX_PACKAGES}|g" \
 		"${_FILE}"
 	fi
 done