fix merge-event-log-tags.py deprecation warning
fix merge-event-log-tags.py deprecation warning

Prefer using the hashlib module if it's available, instead of the
deprecated md5 module.

Change-Id: Id5e50af125ae47f34d011d8612059424472c7c3f

Hybrid-Power/startsync,xorware/android_build,xorware/android_build,knone1/platform_manifest,RR-msm7x30/platform_manifest,fallouttester/platform_manifest,see4ri/lolili,hagar006/platform_manifest,pranav01/platform_manifest,ND-3500/platform_manifest,xorware/android_build,xorware/android_build,xorware/android_build