Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I0ce850de85e0de6a5472dd142f738856142db9ec
diff --git a/libs/binder/IAppOpsService.cpp b/libs/binder/IAppOpsService.cpp
index 9558376..638ae5c 100644
--- a/libs/binder/IAppOpsService.cpp
+++ b/libs/binder/IAppOpsService.cpp
@@ -31,7 +31,7 @@
 class BpAppOpsService : public BpInterface<IAppOpsService>
 {
 public:
-    BpAppOpsService(const sp<IBinder>& impl)
+    explicit BpAppOpsService(const sp<IBinder>& impl)
         : BpInterface<IAppOpsService>(impl)
     {
     }