Pii info logging cleanup in SubscriptionManager

A BR showed that some PII was being logged in
SubscriptionManager#getActiveSubscriptionInfoForSimSlotIndex.
After examination, it looks like the DBG var was set to true
and never set back to false causing PII to be logged.

bug: 189354214
Test: none
Change-Id: I9bde1a464d566ed7f2d178848100b5d38ffd8f21