Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I88cfccb77a25c74df11adc365e7a495cb67cb018
diff --git a/libvehiclenetwork/native/IVehicleNetwork.cpp b/libvehiclenetwork/native/IVehicleNetwork.cpp
index 528034c..0b78f36 100644
--- a/libvehiclenetwork/native/IVehicleNetwork.cpp
+++ b/libvehiclenetwork/native/IVehicleNetwork.cpp
@@ -56,7 +56,7 @@
 
 class BpVehicleNetwork : public BpInterface<IVehicleNetwork> {
 public:
-    BpVehicleNetwork(const sp<IBinder> & impl)
+    explicit BpVehicleNetwork(const sp<IBinder> & impl)
         : BpInterface<IVehicleNetwork>(impl) {
     }