Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I625fbab25f16282c2ea929cd16283d9d146fa17b
diff --git a/media/libmedia/IMediaHTTPService.cpp b/media/libmedia/IMediaHTTPService.cpp
index 0c16a2b..062a07a 100644
--- a/media/libmedia/IMediaHTTPService.cpp
+++ b/media/libmedia/IMediaHTTPService.cpp
@@ -30,7 +30,7 @@
 };
 
 struct BpMediaHTTPService : public BpInterface<IMediaHTTPService> {
-    BpMediaHTTPService(const sp<IBinder> &impl)
+    explicit BpMediaHTTPService(const sp<IBinder> &impl)
         : BpInterface<IMediaHTTPService>(impl) {
     }