Frameworks/base: Wall Werror in common_time

Turn on warnings and errors in common_time.

Fix a code path in CommonTimeServer::handleSyncResponse in which
and uninitialized variable is returned.

Change-Id: I2f80f063c625f032266647d0507f573370202707
diff --git a/libs/common_time/main.cpp b/libs/common_time/main.cpp
index 49eb30a..ac52c85 100644
--- a/libs/common_time/main.cpp
+++ b/libs/common_time/main.cpp
@@ -27,7 +27,7 @@
 
 #include "common_time_server.h"
 
-int main(int argc, char *argv[]) {
+int main() {
     using namespace android;
 
     sp<CommonTimeServer> service = new CommonTimeServer();