Add logging for isRoamIndForHomeSystem

ServiceStateTracker seems to be setting roaming=true even when the
cdma home system list means it should be false. This CL adds some
logging to better diagnose the problem.

Bug: 62721891
Test: built locally
Change-Id: I2d0bc5646ab707ffc9814a788dbd6af1dd4a615a
Merged-In: I2d0bc5646ab707ffc9814a788dbd6af1dd4a615a