GE Attenuator / Mbed 2 deprecated VAM_DAX_RELIABILITY

update hcsr04.cpp by changing 20000 to 2000

Dependencies:   Stepper mbed SDFileSystem Ultrasonic PinDetect millis

Diff: HCSR04.lib

Revision:
3:fd2ca631ab44
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HCSR04.lib	Sat Oct 13 02:19:16 2018 +0000
@@ -0,0 +1,1 @@
+https://os.mbed.com/users/rschimpf78/code/Ultrasonic/#52885486729c