Make member function as const whenever possible.

Test: unit tests passed.
Change-Id: I751cabf305a4b5aa2095853cc951837da0df4c78
diff --git a/cmds/statsd/src/StatsService.cpp b/cmds/statsd/src/StatsService.cpp
index 65b3da1..aaf1868 100644
--- a/cmds/statsd/src/StatsService.cpp
+++ b/cmds/statsd/src/StatsService.cpp
@@ -667,7 +667,7 @@
     mProcessor->OnLogEvent(event);
 }
 
-Status StatsService::getData(const String16& key, vector <uint8_t>* output) {
+Status StatsService::getData(const String16& key, vector<uint8_t>* output) {
     IPCThreadState* ipc = IPCThreadState::self();
     ALOGD("StatsService::getData with Pid %i, Uid %i", ipc->getCallingPid(),
           ipc->getCallingUid());