[Resolver-log] Replacing unused debuging functions by LOG(x).

Removing printf/vlog/syslog/ ...etc debuging functions and using LOG(x).
Then we can configure the log verbosity in the resolver with:
// Set the minimum severity level for logging, returning the old severity.
LogSeverity SetMinimumLogSeverity(LogSeverity new_severity);

Bug: 121176138
Test: make; flash;
Test: The default severity is WARNING. Reboot device and check that only
      WARNING/ERROR logs are printed.
Change-Id: Ib8de89a4cba96ded186579ccefaf88031066e508