Opt adbd and init out of property-watcher thread

Bug: http://b/116873221
Bug: http://b/134177005

adbd calls selinux_android_setcon() which will fail if there are
multiple threads in the process.  The reason for boot failures with
coverage-enabled init and property-watcher thread is not clear yet.

Test: cuttlefish with coverage for init and adbd boots.
Change-Id: I0c44e76cc59d12b963e4d5b862683ead2f816cdc
1 file changed