Rename a few things in statsd_config.proto.

This for frameworks/base/

SimpleLogEntryMatcher -> SimpleAtomMatcher.
simple_log_entry_matcher -> simple_atom_matcher
LogEntryMatcher -> AtomMatcher
log_entry_matcher -> atom_matcher

Test: Ran statsd_test.

Change-Id: I7398758e3fab86235897c162884f5ceab3002510