Fix linter warnings in netd tests

Test: tests/runtests.sh
Change-Id: Id06480fa3c1fc04f5669c42b87b263b46bf614fd
diff --git a/server/BandwidthControllerTest.cpp b/server/BandwidthControllerTest.cpp
index 95af148..7a3a057 100644
--- a/server/BandwidthControllerTest.cpp
+++ b/server/BandwidthControllerTest.cpp
@@ -115,13 +115,11 @@
         return mBw.runIptablesAlertFwdCmd(a, b, c);
     }
 
-    int setCostlyAlert(const std::string a, int64_t b, int64_t *c) {
+    int setCostlyAlert(const std::string& a, int64_t b, int64_t* c) {
         return mBw.setCostlyAlert(a, b, c);
     }
 
-    int removeCostlyAlert(const std::string a, int64_t *b) {
-        return mBw.removeCostlyAlert(a, b);
-    }
+    int removeCostlyAlert(const std::string& a, int64_t* b) { return mBw.removeCostlyAlert(a, b); }
 
     void expectUpdateQuota(uint64_t quota) {
         uintptr_t dummy;