logd: don't use SIGHUP to reinitialize

It doesn't look like there are any users, since there is a much better
mechanism, `logd --reinit` that exists for this behavior.  The
settings app and init.rc use that mechanism and they are the two major
clients that force logd to reinitialize.

This saves us from creating a thread and marginally cleans up
main.cpp.

Test: log reinitialization works
Change-Id: Icdb56b6f59adbba82812231a4f3a6ffd1a7955fc
diff --git a/logd/LogUtils.h b/logd/LogUtils.h
index fa9f398..f9cd42d 100644
--- a/logd/LogUtils.h
+++ b/logd/LogUtils.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef _LOGD_LOG_UTILS_H__
-#define _LOGD_LOG_UTILS_H__
+#pragma once
 
 #include <sys/cdefs.h>
 #include <sys/types.h>
@@ -41,7 +40,6 @@
 
 // Furnished in LogTags.cpp. Thread safe.
 const char* tagToName(uint32_t tag);
-void ReReadEventLogTags();
 
 // Furnished by LogKlog.cpp
 char* log_strntok_r(char* s, ssize_t& len, char*& saveptr, ssize_t& sublen);
@@ -72,5 +70,3 @@
     return (id == LOG_ID_MAIN) || (id == LOG_ID_SYSTEM) ||
            (id == LOG_ID_RADIO) || (id == LOG_ID_EVENTS);
 }
-
-#endif  // _LOGD_LOG_UTILS_H__