logd: rename FlushToResult to FilterResult

This was a typo; the enum corresponds to the result of the 'Filter'
function, not the 'FlushTo' function.

Test: build
Change-Id: Ib46f0646570b6dbaac17ae9fc95c990128cdbe72
diff --git a/logd/LogBuffer.h b/logd/LogBuffer.h
index 7f1e128..d38c018 100644
--- a/logd/LogBuffer.h
+++ b/logd/LogBuffer.h
@@ -27,7 +27,7 @@
 
 class LogWriter;
 
-enum class FlushToResult {
+enum class FilterResult {
     kSkip,
     kStop,
     kWrite,
@@ -48,7 +48,7 @@
     virtual uint64_t FlushTo(
             LogWriter* writer, uint64_t start,
             pid_t* last_tid,  // nullable
-            const std::function<FlushToResult(const LogBufferElement* element)>& filter) = 0;
+            const std::function<FilterResult(const LogBufferElement* element)>& filter) = 0;
 
     virtual bool Clear(log_id_t id, uid_t uid) = 0;
     virtual unsigned long GetSize(log_id_t id) = 0;