Change some log messages from Debugf to Infof
Change some log messages from Debugf to Infof

This is to maintain exiting behavior. Currently, there are no log
level control, and therefore DEBUG messages are always output.

With the CoreDNS debugger, Debugf() messages are only output if
if CoreDNS enable the debug plugin.

infobloxopen/themis,vasili-v/themis,vasili-v/themis,yuewko/themis,infobloxopen/policy-box,yuewko/themis