Fix find_api_violations script.

- The log tag seems to have changed, no longer zygote[64]
- Add option to output just method signatures, for adding to the light
  greylist.

Test: $ find_api_violations.pl -s -b --nolightgrey < bugreport.txt
Change-Id: I31fd21c0d77e23188c010a412db41b4bcdc53ee8