servicemanager: log for service collision

It's pretty easy to accidentally install two instances
of a HAL. We've seen this in HIDL a lot, and we expect
to see it some in AIDL, because we don't have a build
guarantee.

Bug: 247882470
Test: run binderLibTest twice and once and see PID log
Change-Id: I848a767c2b3a4f089fd6742979bd94708cce2c94